I was looking in post for this bug, maybe this is an old issue. Here is one I saw during a race on Daytona oval doing 20 laps which require a pit stop for most cars and AI.
AI cars entering pit area.
Ai car in PIT Area
AI Cars out of Pit area
There was only 1 lap left but they stay merged all they way to finish. There was movement like one would gain or fall behind but they stuck on each other. Hard to say if they would separate since the AI was following the same path and similar speeds.