The AI don’t experience any tyre temperature overheating or engine overheating. It’s clearly shown during changing track conditions. Ai drivers on wet or intermediate tyres on a completely dry track do not experience any overheating, their tyres are locked to a set optimal tyre temperature similar to time trial.
Its also clearly visible racing at a track such as Monza that the Ai do not experience any engine overheating or, usually it takes about 5 laps being in the turbulent air of the car in front to start experiencing overheating and reduce power, but the Ai can be behind the player or another ai driver and not suffer the same experience.
its the same issue on all tracks in any game mode on any difficulty and on any settings.