I don't know if the bug is already known.
It is often the case that the AI has problems overtaking other cars. In particular, this leads to strange results if the AI drives on a 2 stop strategy (top 10 drivers) and the others on 1 stop strategy. The AI drives several laps behind the train of slow drivers (2 seconds slower per lap) until these cars come to the pit stop. They are then faster again immediately, but have to go to the pits again and are behind the slow cars again - this problem is even more serious if it is a slow route or it is difficult to overtake there. (Monaco, Spain, Hungary, Singapore for example)
I hope you can fix this bug - the error occurs especially in 50% races.
Thanks and best regards