diff --git a/src/hb-ot-shape-complex-arabic.cc b/src/hb-ot-shape-complex-arabic.cc
index 31e0a1131..a3f528dcf 100644
--- a/src/hb-ot-shape-complex-arabic.cc
+++ b/src/hb-ot-shape-complex-arabic.cc
@@ -38,6 +38,28 @@
 
 #define HB_BUFFER_SCRATCH_FLAG_ARABIC_HAS_STCH HB_BUFFER_SCRATCH_FLAG_COMPLEX0
 
+/* See:
+ * https://github.com/behdad/harfbuzz/commit/6e6f82b6f3dde0fc6c3c7d991d9ec6cfff57823d#commitcomment-14248516 */
+#define HB_ARABIC_GENERAL_CATEGORY_IS_WORD(gen_cat) \
+	(FLAG_SAFE (gen_cat) & \
+	 (FLAG (HB_UNICODE_GENERAL_CATEGORY_UNASSIGNED) | \
+	  FLAG (HB_UNICODE_GENERAL_CATEGORY_PRIVATE_USE) | \
+	  /*FLAG (HB_UNICODE_GENERAL_CATEGORY_LOWERCASE_LETTER) |*/ \
+	  FLAG (HB_UNICODE_GENERAL_CATEGORY_MODIFIER_LETTER) | \
+	  FLAG (HB_UNICODE_GENERAL_CATEGORY_OTHER_LETTER) | \
+	  /*FLAG (HB_UNICODE_GENERAL_CATEGORY_TITLECASE_LETTER) |*/ \
+	  /*FLAG (HB_UNICODE_GENERAL_CATEGORY_UPPERCASE_LETTER) |*/ \
+	  FLAG (HB_UNICODE_GENERAL_CATEGORY_SPACING_MARK) | \
+	  FLAG (HB_UNICODE_GENERAL_CATEGORY_ENCLOSING_MARK) | \
+	  FLAG (HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK) | \
+	  FLAG (HB_UNICODE_GENERAL_CATEGORY_DECIMAL_NUMBER) | \
+	  FLAG (HB_UNICODE_GENERAL_CATEGORY_LETTER_NUMBER) | \
+	  FLAG (HB_UNICODE_GENERAL_CATEGORY_OTHER_NUMBER) | \
+	  FLAG (HB_UNICODE_GENERAL_CATEGORY_CURRENCY_SYMBOL) | \
+	  FLAG (HB_UNICODE_GENERAL_CATEGORY_MODIFIER_SYMBOL) | \
+	  FLAG (HB_UNICODE_GENERAL_CATEGORY_MATH_SYMBOL) | \
+	  FLAG (HB_UNICODE_GENERAL_CATEGORY_OTHER_SYMBOL)))
+
 
 /*
  * Joining types:
@@ -501,7 +523,7 @@ apply_stch (const hb_ot_shape_plan_t *plan,
       while (context &&
 	     !hb_in_range<unsigned> (info[context - 1].arabic_shaping_action(), STCH_FIXED, STCH_REPEATING) &&
 	     (_hb_glyph_info_is_default_ignorable (&info[context - 1]) ||
-	      HB_UNICODE_GENERAL_CATEGORY_IS_WORD (_hb_glyph_info_get_general_category (&info[context - 1]))))
+	      HB_ARABIC_GENERAL_CATEGORY_IS_WORD (_hb_glyph_info_get_general_category (&info[context - 1]))))
       {
 	context--;
 	w_total += pos[context].x_advance;
diff --git a/src/hb-unicode-private.hh b/src/hb-unicode-private.hh
index 5d544ec93..ecbec513c 100644
--- a/src/hb-unicode-private.hh
+++ b/src/hb-unicode-private.hh
@@ -362,24 +362,4 @@ extern HB_INTERNAL const hb_unicode_funcs_t _hb_unicode_funcs_nil;
 	 (FLAG (HB_UNICODE_GENERAL_CATEGORY_SPACING_MARK) | \
 	  FLAG (HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK)))
 
-#define HB_UNICODE_GENERAL_CATEGORY_IS_WORD(gen_cat) \
-	(FLAG_SAFE (gen_cat) & \
-	 (FLAG (HB_UNICODE_GENERAL_CATEGORY_UNASSIGNED) | \
-	  FLAG (HB_UNICODE_GENERAL_CATEGORY_PRIVATE_USE) | \
-	  FLAG (HB_UNICODE_GENERAL_CATEGORY_LOWERCASE_LETTER) | \
-	  FLAG (HB_UNICODE_GENERAL_CATEGORY_MODIFIER_LETTER) | \
-	  FLAG (HB_UNICODE_GENERAL_CATEGORY_OTHER_LETTER) | \
-	  FLAG (HB_UNICODE_GENERAL_CATEGORY_TITLECASE_LETTER) | \
-	  FLAG (HB_UNICODE_GENERAL_CATEGORY_UPPERCASE_LETTER) | \
-	  FLAG (HB_UNICODE_GENERAL_CATEGORY_SPACING_MARK) | \
-	  FLAG (HB_UNICODE_GENERAL_CATEGORY_ENCLOSING_MARK) | \
-	  FLAG (HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK) | \
-	  FLAG (HB_UNICODE_GENERAL_CATEGORY_DECIMAL_NUMBER) | \
-	  FLAG (HB_UNICODE_GENERAL_CATEGORY_LETTER_NUMBER) | \
-	  FLAG (HB_UNICODE_GENERAL_CATEGORY_OTHER_NUMBER) | \
-	  FLAG (HB_UNICODE_GENERAL_CATEGORY_CURRENCY_SYMBOL) | \
-	  FLAG (HB_UNICODE_GENERAL_CATEGORY_MODIFIER_SYMBOL) | \
-	  FLAG (HB_UNICODE_GENERAL_CATEGORY_MATH_SYMBOL) | \
-	  FLAG (HB_UNICODE_GENERAL_CATEGORY_OTHER_SYMBOL)))
-
 #endif /* HB_UNICODE_PRIVATE_HH */
diff --git a/test/shaping/texts/in-tree/shaper-arabic/script-syriac/misc/abbreviation-mark.txt b/test/shaping/texts/in-tree/shaper-arabic/script-syriac/misc/abbreviation-mark.txt
index 80a568c73..a450678d5 100644
--- a/test/shaping/texts/in-tree/shaper-arabic/script-syriac/misc/abbreviation-mark.txt
+++ b/test/shaping/texts/in-tree/shaper-arabic/script-syriac/misc/abbreviation-mark.txt
@@ -5,7 +5,7 @@
 ܐ܏ܒܓܕ 
 ܐ܏ܒܓܕܐ 
 ܐ܏ܒܓܕܐܐܐܐܐܐܐܐܐ 
+ܐ܏ܒܓܕܐ܏ܐܐܐ܏ܐ܏ܐܐܐܐ 
 ܐ܏ܒܓܕܓܓܓܓܓܓ 
 ܐ܏ܒܓ 
-
-
+܏ܫܘabcܒ.