Nope. I have no folders in the auto import, and then it shouldn't do anything, right? I have nothing automated, I control everything manually when it comes to my library!
Edit: And the first library backup from 12 is messed up with wrong genres, but the last 11.1, taken just before I uninstalled that and installed 12, is not messed up, so it happened within those 10 minutes. Sounds to me like a conversion error.