diff --git a/source/blender/blenkernel/intern/object.c b/source/blender/blenkernel/intern/object.c
index 86326655cfe..0cf2993133c 100644
--- a/source/blender/blenkernel/intern/object.c
+++ b/source/blender/blenkernel/intern/object.c
@@ -1124,6 +1124,12 @@ void BKE_object_copy_data(Main *UNUSED(bmain), Object *ob_dst, const Object *ob_
 		ob_dst->matbits = MEM_dupallocN(ob_src->matbits);
 		ob_dst->totcol = ob_src->totcol;
 	}
+	else if (ob_dst->mat != NULL || ob_dst->matbits != NULL) {
+		/* This shall not be needed, but better be safe than sorry. */
+		BLI_assert(!"Object copy: non-NULL material pointers with zero counter, should not happen.");
+		ob_dst->mat = NULL;
+		ob_dst->matbits = NULL;
+	}
 
 	if (ob_src->iuser) ob_dst->iuser = MEM_dupallocN(ob_src->iuser);