SO sorry to take this long to respond, I wasn’t notified of this showing up on the site.
In case this is still relevant, and you didn’t contact me directly:
Try going to Info->Diagnostics, then tap Clear Cache. It may complain that you have unsaved data, say you want to clear it anyway. Repeat this until it no longer complains of unsaved data.
After that is done, go to Info->Diagnostics->Backups of previously saved hunts. You should see copies of saved versions of your hunt, most recent at the top. Open the one you want, make a small change (like removing the ‘Copy’ from the title), and then save it. If it successfully saves, you should be navigated to the hunt overview screen of the hunt.