I thikn this is an already known bug, but it's kind of a scary one ... looks like something wrong with the quaternions ...
https://www.youtube.com/v/XOKPHSRXyjY
I have the replay, if needed.
Bugs the hell out of me (pun fully intended), being a wheelie fanatic and actually being able to scrape fender and bring it back over, it ruins replays of good wheelies. :(