AI pitting every lap during heavy rain

Ok, about 2 weeks ago I did a full length race on I think imola, and it was heavy rain the whole race, at the end (about 5-6 laps to the end) every AI just started pitting every lap for wets, again and again. I thought it was a fluke but now I've confirmed that it's definitely a pretty big bug as today I was playing Austria, also full length (71 laps) and the conditions were the same, heavy rain. All normal till the 60th lap where everyone started pitting every lap (again), well maybe not every lap but as you can see from the picture some of them reached up to 8 pit stops (on a 1 stopper). I really have no idea if anyone noticed this or if anyone actually does full length races but yeah.. It is pretty annoying and I don't really think I can do anything about it myself.