diff --git a/src/hb-ot-layout-gpos-private.h b/src/hb-ot-layout-gpos-private.h
index 7d468d26d6fed61280264ec89e16c0a649715bfd..5ad28a619214902d8379ebd419d61914538ee25b 100644
--- a/src/hb-ot-layout-gpos-private.h
+++ b/src/hb-ot-layout-gpos-private.h
@@ -264,6 +264,8 @@ struct SinglePosFormat1
       return false;
 
     valueFormat.apply_value (layout, (const char *) this, values, CURPOSITION ());
+
+    buffer->in_pos++;
     return true;
   }
 
@@ -297,6 +299,8 @@ struct SinglePosFormat2
     valueFormat.apply_value (layout, (const char *) this,
 			     values + index * valueFormat.get_len (),
 			     CURPOSITION ());
+
+    buffer->in_pos++;
     return true;
   }