I have started the dungeon, talked to Winthrop, met him in the maproom, defeated the prince, returned with the staff to the map room, Winthrop told me to defeat Krokenkamon, which I did, returned to map room. Before I even stepped up on the platform, he congratulated me. Now he is not in the room, and it is still telling me to explore the platform. No X option appears. I have logged of the game and returned and it still does not register as finished.