Originally posted by The Smoke Monster
There's really no fix. Anything not-normal you have in that room? In fact, a screenshot might help us find out- interplay between sprites may cause something.
If there isn't anything like that, I guess you are just out of luck. It's annoying to say, but corruptions like this apparently happen. I can only say I hope you have a backup.
*shrug* I guess I should just remove the damn boo. Ugh.