diff --git a/src/mon.c b/src/mon.c
index 9b734d0db..4f0a13d4a 100644
--- a/src/mon.c
+++ b/src/mon.c
@@ -3762,7 +3762,7 @@ boolean msg;      /* "The oldmon turns into a newmon!" */
     /* take on the new form... */
     set_mon_data(mtmp, mdat);
 
-    if (!leashable(mtmp))
+    if (mtmp->mleashed && !leashable(mtmp))
         m_unleash(mtmp, TRUE);
 
     if (emits_light(olddata) != emits_light(mtmp->data)) {