Well yes, I expect a wipe at release. That's entirely different. This is a beta and I expect some problems, otherwise I'd be sitting here yelling about getting my money back. Which I would be doing in the full release if something like this happened and the company shrugged and said "can't help you, man" or "go cheat your way back." The closest I ever came to that though was Daggerfall's corrupted savegame issues.
It's not being reported as a bug because I have no idea if it is a bug; it could have been some kind of damage to their server or something. The fact no one else has run across it yet makes me suspicious it's not easily repeatable if it's a bug at all. It was the second new subdungeon I found - the other involved a blue guitar. I didn't know until after I reloaded how serious it was, so I didn't pay nearly as much attention as I would have if I knew it wasn't going to be a typical crash. All I know for sure is the crash display said "invocation" in it, but I don't know if that display ever changes. That's the first time I've tried reading any of it at all; I just saw it come up, shook my head, wished there were a "send bug report" button, and hit exit. Relogged, and was hosed.
Trust me, if I knew it were going to be serious, I'd have done a much better job of reporting what dungeon I was in (I know it was a Normal dungeon, I was there because it was flaming - interestingly enough I still have flaming dungeons and access to Vicious Gaan-Telet, despite the fact that in my real file, I didn't clear Gaan-Telet until after getting all the monster classes. Heck, my second Hard finish was a Vampire.) I know I hard recently been in Cursed Oasis twice, which seems to be a very buggy place for other people. One was a successful Crusader run, I forget the other.