Cars getting stuck behind stationary (or crawling) opponents I'm very familiar with... but the issue is not that they get teleported to the pits. The actual issue is that
they are NOT teleported but stay crawling on the track "injured" like 30 km/h and ruin the races and create traffic issues.
However... that never, ever happens to me with any other cars than Kunos based ones. SD 1982, 1983, 1984, 1988 and also Kunos Lotus98T based 1986 ones. VRC, RSS, ASR, F2004 based... never.
After all these years I haven't really figured out why it happens... and it happens only on specific tracks. Monaco 1988 and Oesterreichring 1979. And it happens only occasionally. Not that often.
The utter stupidity of AC AI is the most blatant on those cases when you drive to the gravel on a chicane and return to the racing line. They are too stupid to overtake you outside the specified fastlane. On straight they can overtake. And of course the lack of blue flag/outlap AI is unforgivable.
But you can "adapt" to those issues with your driving style. But I have a feeling the overtaking and actual racing has improved a lot. Perhaps it's not the new ai... maybe it's just that we have such great quality fastlanes now. As I've said in many occasions anything made by
@Thockard is simpy superb quality. Not say this to kiss anyone's a** but they really are. Races are safe, AI is very fast and there are rarely any kind of issues at all. Combine that with cars that have decent traction (for example Virtua Simulazione Ferrari didn't initially have) and you have excellent racing.
I urge you to try my F2004 based F1 season and do as the instructions say. No CM adjustments but simply the championship mode. You'll see that even the backmarkers won't cause you any trouble in laps 16 and beyond (you get a few backmarkers even in 20 lap races as the individual driver AI skill differences are somewhat dramatic like 89-100). It must be done to achieve realistic QF/race results as the base car is the same.
Third major issue is the AI qualifying. They are absolutely idiotic and often choose the time to leave the pits just when the slowest driver/car passes by. Then they follow them like idiots. Sometimes the best cars/drivers won't get a decent qualfy time because of this. This is rare but it happens.
And you HAVE to do the full qualifying. Otherwise AI cars can't determine how much fuel they need for the full race and they will pit too early. It's the same thing as with the user. You need 2 full QF laps before you'll see the fuel/laps capacity.
But there are a lot of bad tracks with issues. Add bad cars and you have terrible AI. But besides those mentioned major flaws AC ai is much, much better than its reputation (considering all factors are combined well).
It's pretty much like if you drive two similar used Toyota Camrys and the other one has bad brakes, worn out suspension and ignition issues. Then the other one is a pristine example. You can't really say that old Camrys are bad cars. We have so much quality variation in AC mods so it's very hard to say that Assetto Corsa has a "bad AI". Way too much variables.It has major flaws and some really weird quirks, but when With good tracks and cars (and decent settings) it's not a bad AI.
Sure in the early 80's you'll see Keke sliding on the rain in Monaco on several occasions. In the 70's probably even more. We also remember Schumi and Kimi occasionally sliding... and sometimes even modern F1 cars have occasional slides... but aLWAYS in very slow speeds. 
