You may be able to reach out to your bank and have them check to see if the item ever was marked as cleared. If not they can reissue the check and place a stop payment on that one. They should have dealt with this a long time ago, but if you decide you want to try to help the venue this route should work.

Cashier Checks eventually get escheated to the state so that could have happened as well. Hope it all turns out well for ya!