diff --git a/icu4c/source/i18n/dtptngen.cpp b/icu4c/source/i18n/dtptngen.cpp
index 32d3fc4..21f2362 100644
--- a/icu4c/source/i18n/dtptngen.cpp
+++ b/icu4c/source/i18n/dtptngen.cpp
@@ -311,6 +311,16 @@
     return U_SUCCESS(status) ? result.orphan() : nullptr;
 }
 
+DateTimePatternGenerator* U_EXPORT2
+DateTimePatternGenerator::createInstanceNoStdPat(const Locale& locale, UErrorCode& status) {
+    if (U_FAILURE(status)) {
+        return nullptr;
+    }
+    LocalPointer<DateTimePatternGenerator> result(
+            new DateTimePatternGenerator(locale, status, true), status);
+    return U_SUCCESS(status) ? result.orphan() : nullptr;
+}
+
 DateTimePatternGenerator*  U_EXPORT2
 DateTimePatternGenerator::createEmptyInstance(UErrorCode& status) {
     if (U_FAILURE(status)) {
@@ -336,7 +346,7 @@
     }
 }
 
-DateTimePatternGenerator::DateTimePatternGenerator(const Locale& locale, UErrorCode &status) :
+DateTimePatternGenerator::DateTimePatternGenerator(const Locale& locale, UErrorCode &status, UBool skipStdPatterns) :
     skipMatcher(nullptr),
     fAvailableFormatKeyHash(nullptr),
     fDefaultHourFormatChar(0),
@@ -350,7 +360,7 @@
         internalErrorCode = status = U_MEMORY_ALLOCATION_ERROR;
     }
     else {
-        initData(locale, status);
+        initData(locale, status, skipStdPatterns);
     }
 }
 
@@ -489,13 +499,15 @@
 }  // namespace
 
 void
-DateTimePatternGenerator::initData(const Locale& locale, UErrorCode &status) {
+DateTimePatternGenerator::initData(const Locale& locale, UErrorCode &status, UBool skipStdPatterns) {
     //const char *baseLangName = locale.getBaseName(); // unused
 
     skipMatcher = nullptr;
     fAvailableFormatKeyHash=nullptr;
     addCanonicalItems(status);
-    addICUPatterns(locale, status);
+    if (!skipStdPatterns) { // skip to prevent circular dependency when called from SimpleDateFormat::construct
+        addICUPatterns(locale, status);
+    }
     addCLDRData(locale, status);
     setDateTimeFromCalendar(locale, status);
     setDecimalSymbols(locale, status);
diff --git a/icu4c/source/i18n/smpdtfmt.cpp b/icu4c/source/i18n/smpdtfmt.cpp
index 8beadd6..4717899 100644
--- a/icu4c/source/i18n/smpdtfmt.cpp
+++ b/icu4c/source/i18n/smpdtfmt.cpp
@@ -54,6 +54,7 @@
 #include "unicode/udisplaycontext.h"
 #include "unicode/brkiter.h"
 #include "unicode/rbnf.h"
+#include "unicode/dtptngen.h"
 #include "uresimp.h"
 #include "olsontz.h"
 #include "patternprops.h"
@@ -650,6 +651,12 @@
 }
 
 //----------------------------------------------------------------------
+static const UChar* timeSkeletons[4] = {
+    u"jmmsszzzz",   // kFull
+    u"jmmssz",      // kLong
+    u"jmmss",       // kMedium
+    u"jmm",         // kShort
+};
 
 void SimpleDateFormat::construct(EStyle timeStyle,
                                  EStyle dateStyle,
@@ -714,35 +721,75 @@
     fDateOverride.setToBogus();
     fTimeOverride.setToBogus();
 
+    UnicodeString timePattern;
+    if (timeStyle >= kFull && timeStyle <= kShort) {
+        const char* baseLocID = locale.getBaseName();
+        if (baseLocID[0]!=0 && uprv_strcmp(baseLocID,"und")!=0) {
+            UErrorCode useStatus = U_ZERO_ERROR;
+            Locale baseLoc(baseLocID);
+            Locale validLoc(getLocale(ULOC_VALID_LOCALE, useStatus));
+            if (U_SUCCESS(useStatus) && validLoc!=baseLoc) {
+                bool useDTPG = false;
+                const char* baseReg = baseLoc.getCountry(); // empty string if no region
+                if ((baseReg[0]!=0 && uprv_strncmp(baseReg,validLoc.getCountry(),ULOC_COUNTRY_CAPACITY)!=0)
+                        || uprv_strncmp(baseLoc.getLanguage(),validLoc.getLanguage(),ULOC_LANG_CAPACITY)!=0) {
+                    // use DTPG if
+                    // * baseLoc has a region and validLoc does not have the same one (or has none), OR
+                    // * validLoc has a different language code than baseLoc
+                    useDTPG = true;
+                }
+                if (useDTPG) {
+                    // The standard time formats may have the wrong time cycle, because:
+                    // the valid locale differs in important ways (region, language) from
+                    // the base locale.
+                    // We could *also* check whether they do actually have a mismatch with
+                    // the time cycle preferences for the region, but that is a lot more
+                    // work for little or no additional benefit, since just going ahead
+                    // and always synthesizing the time format as per the following should
+                    // create a locale-appropriate pattern with cycle that matches the
+                    // region preferences anyway.
+                    LocalPointer<DateTimePatternGenerator> dtpg(DateTimePatternGenerator::createInstanceNoStdPat(locale, useStatus));
+                    if (U_SUCCESS(useStatus)) {
+                        UnicodeString timeSkeleton(TRUE, timeSkeletons[timeStyle], -1);
+                        timePattern = dtpg->getBestPattern(timeSkeleton, useStatus);
+                    }
+                }
+            }
+        }
+    }
+
     // if the pattern should include both date and time information, use the date/time
     // pattern string as a guide to tell use how to glue together the appropriate date
     // and time pattern strings.
     if ((timeStyle != kNone) && (dateStyle != kNone))
     {
-        currentBundle.adoptInstead(
-                ures_getByIndex(dateTimePatterns.getAlias(), (int32_t)timeStyle, NULL, &status));
-        if (U_FAILURE(status)) {
-           status = U_INVALID_FORMAT_ERROR;
-           return;
-        }
-        switch (ures_getType(currentBundle.getAlias())) {
-            case URES_STRING: {
-               resStr = ures_getString(currentBundle.getAlias(), &resStrLen, &status);
-               break;
-            }
-            case URES_ARRAY: {
-               resStr = ures_getStringByIndex(currentBundle.getAlias(), 0, &resStrLen, &status);
-               ovrStr = ures_getStringByIndex(currentBundle.getAlias(), 1, &ovrStrLen, &status);
-               fTimeOverride.setTo(TRUE, ovrStr, ovrStrLen);
-               break;
-            }
-            default: {
+        UnicodeString tempus1(timePattern);
+        if (tempus1.length() == 0) {
+            currentBundle.adoptInstead(
+                    ures_getByIndex(dateTimePatterns.getAlias(), (int32_t)timeStyle, NULL, &status));
+            if (U_FAILURE(status)) {
                status = U_INVALID_FORMAT_ERROR;
                return;
             }
-        }
+            switch (ures_getType(currentBundle.getAlias())) {
+                case URES_STRING: {
+                   resStr = ures_getString(currentBundle.getAlias(), &resStrLen, &status);
+                   break;
+                }
+                case URES_ARRAY: {
+                   resStr = ures_getStringByIndex(currentBundle.getAlias(), 0, &resStrLen, &status);
+                   ovrStr = ures_getStringByIndex(currentBundle.getAlias(), 1, &ovrStrLen, &status);
+                   fTimeOverride.setTo(TRUE, ovrStr, ovrStrLen);
+                   break;
+                }
+                default: {
+                   status = U_INVALID_FORMAT_ERROR;
+                   return;
+                }
+            }
 
-        UnicodeString tempus1(TRUE, resStr, resStrLen);
+            tempus1.setTo(TRUE, resStr, resStrLen);
+        }
 
         currentBundle.adoptInstead(
                 ures_getByIndex(dateTimePatterns.getAlias(), (int32_t)dateStyle, NULL, &status));
@@ -784,29 +831,32 @@
     // pattern string from the resources
     // setTo() - see DateFormatSymbols::assignArray comments
     else if (timeStyle != kNone) {
-        currentBundle.adoptInstead(
-                ures_getByIndex(dateTimePatterns.getAlias(), (int32_t)timeStyle, NULL, &status));
-        if (U_FAILURE(status)) {
-           status = U_INVALID_FORMAT_ERROR;
-           return;
-        }
-        switch (ures_getType(currentBundle.getAlias())) {
-            case URES_STRING: {
-               resStr = ures_getString(currentBundle.getAlias(), &resStrLen, &status);
-               break;
-            }
-            case URES_ARRAY: {
-               resStr = ures_getStringByIndex(currentBundle.getAlias(), 0, &resStrLen, &status);
-               ovrStr = ures_getStringByIndex(currentBundle.getAlias(), 1, &ovrStrLen, &status);
-               fDateOverride.setTo(TRUE, ovrStr, ovrStrLen);
-               break;
-            }
-            default: {
+        fPattern.setTo(timePattern);
+        if (fPattern.length() == 0) {
+            currentBundle.adoptInstead(
+                    ures_getByIndex(dateTimePatterns.getAlias(), (int32_t)timeStyle, NULL, &status));
+            if (U_FAILURE(status)) {
                status = U_INVALID_FORMAT_ERROR;
                return;
             }
+            switch (ures_getType(currentBundle.getAlias())) {
+                case URES_STRING: {
+                   resStr = ures_getString(currentBundle.getAlias(), &resStrLen, &status);
+                   break;
+                }
+                case URES_ARRAY: {
+                   resStr = ures_getStringByIndex(currentBundle.getAlias(), 0, &resStrLen, &status);
+                   ovrStr = ures_getStringByIndex(currentBundle.getAlias(), 1, &ovrStrLen, &status);
+                   fDateOverride.setTo(TRUE, ovrStr, ovrStrLen);
+                   break;
+                }
+                default: {
+                   status = U_INVALID_FORMAT_ERROR;
+                   return;
+                }
+            }
+            fPattern.setTo(TRUE, resStr, resStrLen);
         }
-        fPattern.setTo(TRUE, resStr, resStrLen);
     }
     else if (dateStyle != kNone) {
         currentBundle.adoptInstead(
diff --git a/icu4c/source/i18n/unicode/dtptngen.h b/icu4c/source/i18n/unicode/dtptngen.h
index dd99d58..828c0a9 100644
--- a/icu4c/source/i18n/unicode/dtptngen.h
+++ b/icu4c/source/i18n/unicode/dtptngen.h
@@ -77,6 +77,13 @@
 #ifndef U_HIDE_INTERNAL_API
 
     /**
+     * For ICU use only. Skips loading the standard date/time patterns (which is done via DateFormat).
+     *
+     * @internal
+     */
+    static DateTimePatternGenerator* U_EXPORT2 createInstanceNoStdPat(const Locale& uLocale, UErrorCode& status);
+
+    /**
      * For ICU use only
      *
      * @internal
@@ -526,7 +533,7 @@
     /**
      * Constructor.
      */
-    DateTimePatternGenerator(const Locale& locale, UErrorCode & status);
+    DateTimePatternGenerator(const Locale& locale, UErrorCode & status, UBool skipStdPatterns = false);
 
     /**
      * Copy constructor.
@@ -573,7 +580,7 @@
         // with #13183, no longer need flags for b, B
     };
 
-    void initData(const Locale &locale, UErrorCode &status);
+    void initData(const Locale &locale, UErrorCode &status, UBool skipStdPatterns = false);
     void addCanonicalItems(UErrorCode &status);
     void addICUPatterns(const Locale& locale, UErrorCode& status);
     void hackTimes(const UnicodeString& hackPattern, UErrorCode& status);
diff --git a/icu4c/source/test/intltest/dtptngts.cpp b/icu4c/source/test/intltest/dtptngts.cpp
index 1b2aa2a..faa850a 100644
--- a/icu4c/source/test/intltest/dtptngts.cpp
+++ b/icu4c/source/test/intltest/dtptngts.cpp
@@ -44,6 +44,7 @@
         TESTCASE(8, test20640_HourCyclArsEnNH);
         TESTCASE(9, testFallbackWithDefaultRootLocale);
         TESTCASE(10, testGetDefaultHourCycle_OnEmptyInstance);
+        TESTCASE(11, test_jConsistencyOddLocales);
         default: name = ""; break;
     }
 }
@@ -1396,7 +1397,9 @@
                      shortPattern.extract(0, shortPattern.length(), spBuf, 32);
                      jPattern.extract(0, jPattern.length(), jpBuf, 32);
                      const char* dfmtCalType = (dfmt->getCalendar())->getType();
-                     errln("ERROR: locale %s, expected j resolved char %s to occur in short time pattern '%s' for %s (best pattern: '%s')", localeID, jcBuf, spBuf, dfmtCalType, jpBuf);
+                     const char* validLoc = dfmt->getLocaleID(ULOC_VALID_LOCALE, status);
+                     errln("ERROR: locale %s (valid %s), expected j resolved char %s to occur in short time pattern '%s' for %s (best pattern: '%s')",
+                             localeID, validLoc, jcBuf, spBuf, dfmtCalType, jpBuf);
                  }
                  break;
              }
@@ -1420,8 +1423,7 @@
         // formerly New Hebrides, now Vanuatu => VU => h.
         {"en_NH", u"h a", u"h:mm a", UDAT_HOUR_CYCLE_12},
         // ch_ZH is a typo (should be zh_CN), but we should fail gracefully.
-        // {"cn_ZH", u"HH", u"H:mm"}, // TODO(ICU-20653): Desired behavior
-        {"cn_ZH", u"HH", u"h:mm a", UDAT_HOUR_CYCLE_23 }, // Actual behavior
+        {"cn_ZH", u"HH", u"HH:mm", UDAT_HOUR_CYCLE_23 }, // Desired & now actual behavior (does this fix ICU-20653?)
         // a non-BCP47 locale without a country code should not fail
         {"ja_TRADITIONAL", u"H時", u"H:mm", UDAT_HOUR_CYCLE_23},
     };
@@ -1507,4 +1509,52 @@
     }
 }
 
+void IntlTestDateTimePatternGeneratorAPI::test_jConsistencyOddLocales() { // ICU-20590
+    static const char* localeIDs[] = {
+        "en", "ro", // known languages 12h / 24h
+        "en-RO", "ro-US",  // known languages with known regions, hour conflict language vs region
+        "en-XZ", "ro-XZ", // known languages 12h / 24h, unknown region
+        "xz-RO", "xz-US",  // unknown language with known regions
+        "xz", // unknown language
+        "xz-ZX",  // unknown language with unknown country
+        "ars", "wuu" // aliased locales
+    };
+    static const UChar* skeleton = u"jm";
+    for (const char* localeID: localeIDs) {
+        UErrorCode status = U_ZERO_ERROR;
+        Locale locale(localeID);
+        LocalPointer<DateFormat> dtfShort(DateFormat::createTimeInstance(DateFormat::kShort, locale), status);
+        if (U_FAILURE(status)) {
+            errln("DateFormat::createTimeInstance failed for locale %s: %s", localeID, u_errorName(status));
+            continue;
+        }
+        LocalPointer<DateFormat> dtfSkel(DateFormat::createInstanceForSkeleton(skeleton, locale, status));
+        if (U_FAILURE(status)) {
+            errln("DateFormat::createInstanceForSkeleton failed for locale %s: %s", localeID, u_errorName(status));
+            continue;
+        }
+        LocalPointer<DateTimePatternGenerator> dtpg(DateTimePatternGenerator::createInstance(locale, status));
+        if (U_FAILURE(status)) {
+            errln("DateTimePatternGenerator::createInstance failed for locale %s: %s", localeID, u_errorName(status));
+            continue;
+        }
+        UnicodeString dtfShortPattern, dtfSkelPattern;
+        dynamic_cast<SimpleDateFormat*>(dtfShort.getAlias())->toPattern(dtfShortPattern);
+        dynamic_cast<SimpleDateFormat*>(dtfSkel.getAlias())->toPattern(dtfSkelPattern);
+        UnicodeString dtpgPattern = (dtpg.getAlias())->getBestPattern(skeleton, status);
+        if (U_FAILURE(status)) {
+            errln("DateTimePatternGenerator::getBestPattern failed for locale %s: %s", localeID, u_errorName(status));
+            continue;
+        }
+        if (dtfShortPattern != dtfSkelPattern || dtfSkelPattern != dtpgPattern) {
+            const char* dtfShortValidLoc = dtfShort->getLocaleID(ULOC_VALID_LOCALE, status);
+            const char* dtfShortActualLoc = dtfShort->getLocaleID(ULOC_ACTUAL_LOCALE, status);
+            errln(UnicodeString("For locale ") + localeID +
+                    " expected same pattern from DateTimePatGen: " + dtpgPattern +
+                    ", DateFmt-forSkel: " + dtfSkelPattern + ", DateFmt-short: "  + dtfShortPattern +
+                    "; latter has validLoc " + dtfShortValidLoc + ", actualLoc " + dtfShortActualLoc);
+        }
+    }
+}
+
 #endif /* #if !UCONFIG_NO_FORMATTING */
diff --git a/icu4c/source/test/intltest/dtptngts.h b/icu4c/source/test/intltest/dtptngts.h
index 90f65c9..b3fb02e 100644
--- a/icu4c/source/test/intltest/dtptngts.h
+++ b/icu4c/source/test/intltest/dtptngts.h
@@ -36,6 +36,7 @@
     void test20640_HourCyclArsEnNH();
     void testFallbackWithDefaultRootLocale();
     void testGetDefaultHourCycle_OnEmptyInstance();
+    void test_jConsistencyOddLocales();
 };
 
 #endif /* #if !UCONFIG_NO_FORMATTING */
diff --git a/icu4j/main/classes/core/src/com/ibm/icu/text/DateTimePatternGenerator.java b/icu4j/main/classes/core/src/com/ibm/icu/text/DateTimePatternGenerator.java
index 17fb34b..8a09b68 100644
--- a/icu4j/main/classes/core/src/com/ibm/icu/text/DateTimePatternGenerator.java
+++ b/icu4j/main/classes/core/src/com/ibm/icu/text/DateTimePatternGenerator.java
@@ -125,7 +125,7 @@
         }
 
         result = new DateTimePatternGenerator();
-        result.initData(uLocale);
+        result.initData(uLocale, false);
 
         // freeze and cache
         result.freeze();
@@ -133,16 +133,39 @@
         return result;
     }
 
-    private void initData(ULocale uLocale) {
+    /**
+     * Construct a non-frozen instance of DateTimePatternGenerator for a
+     * given locale that skips using the standard date and time patterns.
+     * Because this is different than the normal instance for the locale,
+     * it does not set or use the cache.
+     * @param uLocale The locale to pass.
+     * @internal
+     * @deprecated This API is ICU internal only.
+     */
+    @Deprecated
+    public static DateTimePatternGenerator getInstanceNoStdPat(ULocale uLocale) {
+        DateTimePatternGenerator result = new DateTimePatternGenerator();
+        result.initData(uLocale, true);
+        return result;
+    }
+
+    private void initData(ULocale uLocale, boolean skipStdPatterns) {
         // This instance of PatternInfo is required for calling some functions.  It is used for
         // passing additional information to the caller.  We won't use this extra information, but
         // we still need to make a temporary instance.
         PatternInfo returnInfo = new PatternInfo();
 
         addCanonicalItems();
-        addICUPatterns(returnInfo, uLocale);
+        if (!skipStdPatterns) { // skip to prevent circular dependency when used by Calendar
+            addICUPatterns(returnInfo, uLocale);
+        }
         addCLDRData(returnInfo, uLocale);
-        setDateTimeFromCalendar(uLocale);
+        if (!skipStdPatterns) { // also skip to prevent circular dependency from Calendar
+            setDateTimeFromCalendar(uLocale);
+        } else {
+            // instead, since from Calendar we do not care about dateTimePattern, use a fallback
+            setDateTimeFormat("{1} {0}");
+        }
         setDecimalSymbols(uLocale);
         getAllowedHourFormats(uLocale);
         fillInMissing();
diff --git a/icu4j/main/classes/core/src/com/ibm/icu/util/Calendar.java b/icu4j/main/classes/core/src/com/ibm/icu/util/Calendar.java
index 1ae987e..f428731 100644
--- a/icu4j/main/classes/core/src/com/ibm/icu/util/Calendar.java
+++ b/icu4j/main/classes/core/src/com/ibm/icu/util/Calendar.java
@@ -27,6 +27,7 @@
 import com.ibm.icu.impl.SoftCache;
 import com.ibm.icu.text.DateFormat;
 import com.ibm.icu.text.DateFormatSymbols;
+import com.ibm.icu.text.DateTimePatternGenerator;
 import com.ibm.icu.text.SimpleDateFormat;
 import com.ibm.icu.util.ULocale.Category;
 
@@ -3514,6 +3515,13 @@
         "{1} {0}",
         "{1} {0}"
     };
+    // final fallback patterns
+    private static final String[] TIME_SKELETONS = {
+        "jmmsszzzz",    // Full
+        "jmmssz",       // Long
+        "jmmss",        // Medium
+        "jmm"           // Short
+    };
 
     static private DateFormat formatHelper(Calendar cal, ULocale loc, int dateStyle,
             int timeStyle) {
@@ -3615,7 +3623,39 @@
         int patternsSize = dtPatternsRb.getSize();
         String[] dateTimePatterns = new String[patternsSize];
         String[] dateTimePatternsOverrides = new String[patternsSize];
-        for (int i = 0; i < patternsSize; i++) {
+        int i = 0; // index for dateTimePatterns, dateTimePatternsOverrides
+
+        String baseLocID = locale.getBaseName();
+        if (baseLocID.length() > 0 && !baseLocID.equals("und")) {
+            ULocale baseLoc = new ULocale(baseLocID);
+            // The following is different from ICU4C, where we can get the valid locale
+            // for the SimpleDateFormat object. Here we do not have a SimpleDateFormat and
+            // valid locale for the Calendar is a bit meaningless.
+            ULocale validLoc = ULocale.addLikelySubtags(dtPatternsRb.getULocale());
+            if (validLoc != baseLoc) {
+                String baseReg = baseLoc.getCountry();
+                if ((baseReg.length() > 0 && !baseReg.equals(validLoc.getCountry()))
+                        || !baseLoc.getLanguage().equals(validLoc.getLanguage())) {
+                    // use DTPG if the standard time formats may have the wrong time cycle,
+                    // because the valid locale differs in important ways (region, language)
+                    // from the base locale.
+                    // We could *also* check whether they do actually have a mismatch with
+                    // the time cycle preferences for the region, but that is a lot more
+                    // work for little or no additional benefit, since just going ahead
+                    // and always synthesizing the time format as per the following should
+                    // create a locale-appropriate pattern with cycle that matches the
+                    // region preferences anyway.
+                    // In this case we get the first 4 entries of dateTimePatterns using
+                    // DateTimePatternGenerator, not resource data.
+                    DateTimePatternGenerator dtpg = DateTimePatternGenerator.getInstanceNoStdPat(locale);
+                    for (; i < 4; i++) {
+                        dateTimePatterns[i] = dtpg.getBestPattern(TIME_SKELETONS[i]);
+                    }
+                }
+            }
+        }
+
+        for (; i < patternsSize; i++) { // get all or remaining dateTimePatterns entries
             ICUResourceBundle concatenationPatternRb = (ICUResourceBundle) dtPatternsRb.get(i);
             switch (concatenationPatternRb.getType()) {
                 case UResourceBundle.STRING:
diff --git a/icu4j/main/tests/core/src/com/ibm/icu/dev/test/format/DateTimeGeneratorTest.java b/icu4j/main/tests/core/src/com/ibm/icu/dev/test/format/DateTimeGeneratorTest.java
index 0244419..ff462c7 100644
--- a/icu4j/main/tests/core/src/com/ibm/icu/dev/test/format/DateTimeGeneratorTest.java
+++ b/icu4j/main/tests/core/src/com/ibm/icu/dev/test/format/DateTimeGeneratorTest.java
@@ -1737,8 +1737,7 @@
             // en_NH is interesting because NH is a depregated region code.
             {"en_NH", "h a", "h:mm a", "HOUR_CYCLE_12"},
             // ch_ZH is a typo (should be zh_CN), but we should fail gracefully.
-            // {"cn_ZH", "HH", "H:mm"}, // TODO(ICU-20653): Desired behavior
-            {"cn_ZH", "HH", "h:mm a", "HOUR_CYCLE_23"}, // Actual behavior
+            {"cn_ZH", "HH", "HH:mm", "HOUR_CYCLE_23"}, // Desired & now actual behavior (does this fix ICU-20653?)
             // a non-BCP47 locale without a country code should not fail
             {"ja_TRADITIONAL", "H時", "H:mm", "HOUR_CYCLE_23"},
         };
@@ -1759,4 +1758,39 @@
                 cas[3], dtpg.getDefaultHourCycle().toString());
         }
     }
+
+    @Test
+    public void test_jConsistencyOddLocales() { // ICU-20590
+        String[] localeIDs = {
+            "en", "ro", // known languages 12h / 24h
+            "en-RO", "ro-US",  // known languages with known regions, hour conflict language vs region
+            "en-XZ", "ro-XZ", // known languages 12h / 24h, unknown region
+            "xz-RO", "xz-US",  // unknown language with known regions
+            "xz", // unknown language
+            "xz-ZX",  // unknown language with unknown country
+            "ars", "wuu" // aliased locales
+        };
+        final String skeleton = "jm";
+        for (String localeID : localeIDs) {
+            ULocale locale = new ULocale(localeID);
+
+            DateFormat dtfShort = DateFormat.getTimeInstance(DateFormat.SHORT, locale);
+            String dtfShortPattern = ((SimpleDateFormat)dtfShort).toPattern();
+
+            DateFormat dtfSkel = DateFormat.getInstanceForSkeleton(skeleton, locale);
+            String dtfSkelPattern = ((SimpleDateFormat)dtfSkel).toPattern();
+
+            DateTimePatternGenerator dtpg = DateTimePatternGenerator.getInstance(locale);
+            String dtpgPattern = dtpg.getBestPattern(skeleton);
+
+            if (!dtfShortPattern.equals(dtfSkelPattern) || !dtfSkelPattern.equals(dtpgPattern)) {
+                String dtfShortValidLoc = dtfShort.getLocale(ULocale.VALID_LOCALE).getName();
+                String dtfShortActualLoc = dtfShort.getLocale(ULocale.ACTUAL_LOCALE).getName();
+                errln("For locale " + localeID +
+                        " expected same pattern from DateTimePatGen: " + dtpgPattern +
+                        ", DateFmt-forSkel: " + dtfSkelPattern + ", DateFmt-short: "  + dtfShortPattern +
+                        "; latter has validLoc " + dtfShortValidLoc + ", actualLoc " + dtfShortActualLoc);
+            }
+        }
+    }
 }