To start with I have to say that the AI are much better than previous games.
They will race the heck out of you don't really let up easy like in past
versions. There are a few gliches I've noticed.
1) Martinsville - I can't get a race to start with a full field, the AI
keeps wrecking.
2) I forget which track but it was a speedway - On caution I saw an AI car
dive down into the grass around the start/finish line and then just stay
down there till he came to the pits. I've seen it a couple times now. One
time it happened on the last lap before green and with the new rules, the AI
cars refused to pass this car even when he went into the pits. The result
was that I was stuck behind 3 AI cars as they slowed down to a crawl
following this car while it went through the pits, and the rest of the field
went green!