If you have no RBs or FBs on your roster it will put your backup QB at RB. This leads to some crazy stats if your QB is decently fast (even 60 speed can get around 6.5 yards a carry). This is definitely a bug that needs to be addressed, obviously in solo play you can just not do it but for online leagues this could be a gamebreaking issue.
Edit: Also it may be cut off but he only fumbled 7 times. So fumbles don't even it out.