diff --git a/intl/unicharutil/util/nsUnicodeProperties.cpp b/intl/unicharutil/util/nsUnicodeProperties.cpp
index b9c8b83fb2..3f273e1c1e 100644
--- a/intl/unicharutil/util/nsUnicodeProperties.cpp
+++ b/intl/unicharutil/util/nsUnicodeProperties.cpp
@@ -152,8 +152,7 @@ IsClusterExtender(uint32_t aCh, uint8_t aCategory)
 {
     return ((aCategory >= HB_UNICODE_GENERAL_CATEGORY_SPACING_MARK &&
              aCategory <= HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK) ||
-            (GetEmojiPresentation(aCh) == EmojiComponent) ||
-            (aCh == 0x200c) || // ZWNJ
+            (aCh >= 0x200c && aCh <= 0x200d) || // ZWJ, ZWNJ
             (aCh >= 0xff9e && aCh <= 0xff9f));  // katakana sound marks
 }