Think it is on the road as AI does not master rear steering perfectly for the moment
This even happens with tractors. The AI sometimes starts to overdrive massively until it reaches an intersection where it slows down. Thereby the tractor drives curves and not in a strait line. The AI debug though, doesn't show an indicator for that. It seems all normal.
I think it mostly happens when you drive a big cultivator without a front weight.
Yes, having the front wheels not perfectly at the ground, what happens with heavy rear 3 point attached equipment without a weight at the front, make the Tractor unable to steer correctly, what is normal in fact...
But to me it seems like it is almost a bit too strong. I don't have problems with over-steering, even though I notice that the steering is very "spongy" (and I'm not playing with a steering wheel). The AI somehow can't handle it at all.
Well, maybe the AI Drivers are not very experienced
(to be clear: it's nothing bad, i just noticed it)