Odd sort-of fix for allowing //stack to be undone

worldedit-core/src/main/java/com/sk89q/worldedit/EditSession.java

@@ -1469,7 +1469,7 @@ public class EditSession extends PassthroughExtent implements AutoCloseable {
             setSourceMask(null);
             copy.setSourceMask(mask);
         }
-        Operations.completeBlindly(copy);
+        Operations.completeLegacy(copy);
         return this.changes = copy.getAffected();
     }