Did a 50 lap race at Homestead with moderate penalties on, and at one point the lead car brake checked in the corner causing the second place car to rear end them, which ended up causing me to slide into the back of that car as I tried to slow down and avoid it. Looking at the leaderboard a moment later, I saw the game rightfully assigned a penalty to the lead car for causing the incident and neither the second place car nor myself were penalized. In GT7 that likely would have been the reverse and the game would have penalized me for hitting a car, even though I had no way to avoid it and wasn't the one who caused it.
I also noticed that one of the backmarker AI cars had run up 7 seconds(!) of penalties by the end of the race, which makes me wonder if they actually will get disqualified if they cross the 12 second threshold.
(also holy cow they need to fix track re-entry on the Homestead oval, instead of taking you around to the backstretch and having you merge in there it just dumps you onto the racing line at turn 1 in front of everyone. THAT AIN'T RIGHT.)