Yes, it's sufficient, and now it's done too.

git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@3489 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/java/com/threerings/parlor/turn/server/TurnGameManagerDelegate.java

@@ -145,6 +145,10 @@ public class TurnGameManagerDelegate extends GameManagerDelegate
         // and start the next turn if desired
         if (_turnIdx != -1) {
             startTurn();
+
+        } else {
+            // otherwise, clear out the turn holder
+            _turnGame.setTurnHolder(null);
         }
     }