Bug on Forza Motorsport 6/7: Drivatars aren't competitive [XBOX ONE]

I’ve a bug related to the Drivatars: whatever it’s the difficulty set Drivatars aren’t competitve.
This bug is started on Forza 6 and it’s repeated on Forza 7.
Drivatars guide too slow and the game isn’t funny because I get the first position in almost all races effortlessy.
Please solve it.