diff --git a/common/main/an.xml b/common/main/an.xml
index 6aed6517ff5..f36393ecbc6 100644
--- a/common/main/an.xml
+++ b/common/main/an.xml
@@ -1125,8 +1125,8 @@ CLDR data files are interpreted according to the LDML specification (http://unic
 						</intervalFormatItem>
 						<intervalFormatItem id="yMEd">
 							<greatestDifference id="d" draft="unconfirmed">E, d/M/y – E, d/M/y</greatestDifference>
-							<greatestDifference id="M" draft="unconfirmed">E, d/M/y</greatestDifference>
-							<greatestDifference id="y" draft="unconfirmed">E, d/M/Y – E, d/M/Y</greatestDifference>
+							<greatestDifference id="M" draft="unconfirmed">E, d/M/y – E, d/M/y</greatestDifference>
+							<greatestDifference id="y" draft="unconfirmed">E, d/M/y – E, d/M/y</greatestDifference>
 						</intervalFormatItem>
 						<intervalFormatItem id="yMMM">
 							<greatestDifference id="M" draft="unconfirmed">LLL–LLL y</greatestDifference>
diff --git a/common/main/rif.xml b/common/main/rif.xml
index 6dc31325f18..7949f8737f4 100644
--- a/common/main/rif.xml
+++ b/common/main/rif.xml
@@ -1119,7 +1119,7 @@ CLDR data files are interpreted according to the LDML specification (http://unic
 						</intervalFormatItem>
 						<intervalFormatItem id="MEd">
 							<greatestDifference id="d" draft="unconfirmed">E dd/MM – E dd/MM</greatestDifference>
-							<greatestDifference id="M" draft="unconfirmed">E dd/MM</greatestDifference>
+							<greatestDifference id="M" draft="unconfirmed">E dd/MM – E dd/MM</greatestDifference>
 						</intervalFormatItem>
 						<intervalFormatItem id="MMM">
 							<greatestDifference id="M" draft="unconfirmed">MMM – MMM</greatestDifference>
diff --git a/common/main/si.xml b/common/main/si.xml
index 32d6943f55d..111d8cb9b98 100644
--- a/common/main/si.xml
+++ b/common/main/si.xml
@@ -1183,7 +1183,7 @@ Warnings: All cp values have U+FE0F characters removed. See /annotationsDerived/
 							<greatestDifference id="m">HH.mm–HH.mm</greatestDifference>
 						</intervalFormatItem>
 						<intervalFormatItem id="hmv">
-							<greatestDifference id="a">a h.mm – a hhh.mm v</greatestDifference>
+							<greatestDifference id="a">a h.mm – a h.mm v</greatestDifference>
 							<greatestDifference id="h">a h.mm – h.mm v</greatestDifference>
 							<greatestDifference id="m">a h.mm – h.mm v</greatestDifference>
 						</intervalFormatItem>
@@ -1193,7 +1193,7 @@ Warnings: All cp values have U+FE0F characters removed. See /annotationsDerived/
 						</intervalFormatItem>
 						<intervalFormatItem id="hv">
 							<greatestDifference id="a">a h – a h v</greatestDifference>
-							<greatestDifference id="h">a h – h vv</greatestDifference>
+							<greatestDifference id="h">a h – h v</greatestDifference>
 						</intervalFormatItem>
 						<intervalFormatItem id="Hv">
 							<greatestDifference id="H">↑↑↑</greatestDifference>
diff --git a/tools/cldr-code/src/main/java/org/unicode/cldr/test/CheckDates.java b/tools/cldr-code/src/main/java/org/unicode/cldr/test/CheckDates.java
index 82f1cec20c1..c40b4e5993f 100644
--- a/tools/cldr-code/src/main/java/org/unicode/cldr/test/CheckDates.java
+++ b/tools/cldr-code/src/main/java/org/unicode/cldr/test/CheckDates.java
@@ -3,6 +3,8 @@
 import com.google.common.base.Joiner;
 import com.ibm.icu.impl.Relation;
 import com.ibm.icu.text.BreakIterator;
+import com.ibm.icu.text.DateIntervalInfo;
+import com.ibm.icu.text.DateIntervalInfo.PatternInfo;
 import com.ibm.icu.text.DateTimePatternGenerator;
 import com.ibm.icu.text.DateTimePatternGenerator.VariableField;
 import com.ibm.icu.text.MessageFormat;
@@ -1192,6 +1194,33 @@ private void checkPattern(
                                             new Object[] {requiredYearFieldCount, yearFieldCount}));
                 }
             }
+            // check PatternInfo, for CLDR-17827
+            // ICU-22835, DateIntervalInfo.genPatternInfo fails for intervals like LLL - MMM (in fa)
+            if (!(value.contains("LLL") && value.contains("MMM"))) {
+                PatternInfo pattern = DateIntervalInfo.genPatternInfo(value, false);
+                try {
+                    String first = pattern.getFirstPart();
+                    String second = pattern.getSecondPart();
+                    if (first == null || second == null) {
+                        result.add(
+                                new CheckStatus()
+                                        .setCause(this)
+                                        .setMainType(CheckStatus.errorType)
+                                        .setSubtype(Subtype.incorrectDatePattern)
+                                        .setMessage(
+                                                "DateIntervalInfo.PatternInfo returns null for first or second part"));
+                    }
+                } catch (Exception e) {
+                    result.add(
+                            new CheckStatus()
+                                    .setCause(this)
+                                    .setMainType(CheckStatus.errorType)
+                                    .setSubtype(Subtype.incorrectDatePattern)
+                                    .setMessage(
+                                            "DateIntervalInfo.PatternInfo exception {0}",
+                                            new Object[] {e}));
+                }
+            }
         }
 
         if (value.contains("G") && calendar.equals("gregorian")) {