Fresh! When I first updated to 480, checked out to see if my previous version saves were going to be fine - but had a hunch that wouldn't be the case. It wasn't. They were bugged. "No biggie," I thought, "I'll start from scratch".
And, curiously enough, a save I had done *minutes* before the bugged one... was fine, and still is. Actually, I'm still playing that one. Just, somehow, that particular save got screwed somehow. The only particular difference I can tell is that on my bugged savegame, I had killed two cultists in the upper-right corner of the map. When I reloaded my earlier save, I decided to avoid them and just bolt out of there to see if the bug still persisted.