diff --git a/src/hb-font.cc b/src/hb-font.cc
index dc48df80a..445878bfe 100644
--- a/src/hb-font.cc
+++ b/src/hb-font.cc
@@ -1385,6 +1385,7 @@ hb_font_create_sub_font (hb_font_t *parent)
 
   font->x_scale = parent->x_scale;
   font->y_scale = parent->y_scale;
+  font->mults_changed ();
   font->x_ppem = parent->x_ppem;
   font->y_ppem = parent->y_ppem;
   font->ptem = parent->ptem;