I honestly don't know how that is possible then. The event is set up to turn off after it's run, there isn't really any way to mark that you've viewed that event other than to view it, as the switch to determine if it's been viewed or not is tied directly to that event. Regardless, I set up the way to properly review the event, and adjusted the scene reviewer, so you should be able to access the scene reviewer for dungeon 5, and you should be able to properly restart the boss encounter. Thanks again for letting me know, and do let me know if the fix doesn't work. (Patch 0.48.12)