Help a noob understand AI tyre wear

Hello all,

Disclaimer: I'm a noob. I have lots of experience with racing games in general, but very little with Automobilista 2, and I'm rather bad.

tldr: AI doesn't seem to wear their tyres on some circuits. It looks like a bug but I'm not sure.

Car: Formula Ultimate Gen2
AI: 105%, aggression high
Fuel and tyre wear: x2
Race distance: around 120kms

Given the conditions above:
At Kyalami and Spielberg (and possibly more, but these two I can tell for sure), AI keeps on pushing at a more or less steady pace (I imagine the difference is mostly down to the hybrid mode) for the whole race, without ever stopping.

For example:
Spielberg (modern of course). 28 laps, at 14/15, can't remember, my medium tyres were destroyed (I said I'm a noob, didn't I) and I pitted for softs. AI finished the race with 0 pitstops and with a last lap very, very close to their best. This was rather obvious on track too, where I had new softs with which I should have destroyed AI on their "old" softs, but in fact I was only marginally faster.
At Silverstone AI does stop as you would expect.

I'm absolutely loving the game, but this is very off putting.

 

Do you know which classes have this issue?