diff --git a/src/hb-ot-shape.cc b/src/hb-ot-shape.cc
index 459e1229d0b479a6034233c5d55483cf398ff140..a383b78231a102099fcaaea13e3af1fccbdc90a9 100644
--- a/src/hb-ot-shape.cc
+++ b/src/hb-ot-shape.cc
@@ -138,9 +138,9 @@ hb_ot_shape_planner_t::compile (hb_ot_shape_plan_t           &plan,
   }
 
   bool has_kern_mark = plan.apply_kern && hb_ot_layout_has_cross_kerning (face);
-  plan.zero_marks = !plan.apply_kerx && !has_kern_mark;
+  plan.zero_marks = !plan.apply_morx && !plan.apply_kerx && !has_kern_mark;
   plan.has_gpos_mark = !!plan.map.get_1_mask (HB_TAG ('m','a','r','k'));
-  plan.fallback_mark_positioning = !plan.apply_gpos && !plan.apply_kerx && !has_kern_mark;
+  plan.fallback_mark_positioning = !plan.apply_gpos && plan.zero_marks;
 
   /* Currently we always apply trak. */
   plan.apply_trak = plan.requested_tracking && hb_aat_layout_has_tracking (face);