diff --git a/src/hb-ot-shape-complex-indic.cc b/src/hb-ot-shape-complex-indic.cc
index 02aab082c..3cd8fd6c3 100644
--- a/src/hb-ot-shape-complex-indic.cc
+++ b/src/hb-ot-shape-complex-indic.cc
@@ -624,6 +624,8 @@ setup_syllables (const hb_ot_shape_plan_t *plan HB_UNUSED,
 		 hb_buffer_t *buffer)
 {
   find_syllables (buffer);
+  foreach_syllable (buffer, start, end)
+    buffer->unsafe_to_break (start, end);
 }
 
 static int
diff --git a/src/hb-ot-shape-complex-myanmar.cc b/src/hb-ot-shape-complex-myanmar.cc
index 4e912c361..ebd2b4096 100644
--- a/src/hb-ot-shape-complex-myanmar.cc
+++ b/src/hb-ot-shape-complex-myanmar.cc
@@ -297,6 +297,8 @@ setup_syllables (const hb_ot_shape_plan_t *plan HB_UNUSED,
 		 hb_buffer_t *buffer)
 {
   find_syllables (buffer);
+  foreach_syllable (buffer, start, end)
+    buffer->unsafe_to_break (start, end);
 }
 
 static int
diff --git a/src/hb-ot-shape-complex-use.cc b/src/hb-ot-shape-complex-use.cc
index af6870686..a5ab0ab2a 100644
--- a/src/hb-ot-shape-complex-use.cc
+++ b/src/hb-ot-shape-complex-use.cc
@@ -354,6 +354,8 @@ setup_syllables (const hb_ot_shape_plan_t *plan,
 		 hb_buffer_t *buffer)
 {
   find_syllables (buffer);
+  foreach_syllable (buffer, start, end)
+    buffer->unsafe_to_break (start, end);
   setup_rphf_mask (plan, buffer);
   setup_topographical_masks (plan, buffer);
 }