I had this issue too, the only way I was able to bypass it was to run the race behind the leader. Wait until the time hits a low 30 seconds or less then blast your nos and run your lines clean, you should finish your "lap" times about 5-10 seconds faster than the others.
This is the only time I've ever had a problem with a "rubber banding" mechanic in the game.
EA StaffFound a couple of events tricky, but was able to beat them after a couple of attempts, i found that setting your best time at the start of the event the AI will improve every lap, and most often beat you right at the end.
Set a average lap at the start, and make sure you speed up each lap and improve your time, aiming for your best time as close to the end of the event as possible to stop the AI catching up.
