Hi, I have noticed that they can stuck eventually, I didn't pay attention in this case because now it is set somewhere in the middle mixing physical and non-physical driving to preview both logics. The non-physical drive was made for distance to save performance and is more robust than close-up physical driving. These mode switching can cause this, originally the logic was made for physical behaviour.
I use this asset for 3rd person game with Pooling system where I spawn and despawn AIs around a player, so chance of traffic crashes are really low, not like in the demo as cars and people move around non-stop.
Send me a message if I can help assist you to adjust the asset for your game requirements.