Hi
If I have it correct they try to simulate the tyrewear of the AI like our own tyrewear as good as possible, but it aint the same tyremodel you have. Because of the amount of calculation every AI need to simulate the Rfactor2 tyrewear, they are more simplified, but should simulate the same amount of tyrewear you have. The AI drives real clean, so they tend to last a long time with their tyres, I'm still practicing to try to drive as clean as possible, I'm getting better and better but I'm still not at that level. Would be a handy option if you could select how fast the tyrewear of the AI would be.
The second is just a bug from ISI, sure they will fix it in the future, it was the case with other cars before also, and they fixed that.