I just did a 20 minutes race with ADAC GT Masters 2018 cars on Zandvoort using the ADAC GT Masters 2015 rules preset. Those AI cars that pitted in the last possible lap of the pit stop window all apparently rotated their rear tyres because their cars were jacked up and their pit stops took 10 seconds longer. I guess it would be better to disable that feature for the AI because it rarely makes sense both in the game and in real life anyway...
The same thing just happened in Hockenheim. Those AI cars that pitted one lap later all rotated their rear tyres.