interestingly physx also has some kind of sticky tire implementation inside but their code did not help at all. i have made some improvements to the sticky tire code that solves some minor problems and it seems to work fine for most cases. normally current sticky tires should also work most of the time, can you share a video of your problem, how much slope does your vehicle stand on?
how do you make the seamless travel to another level? the logs does not tell much, if we can recreate the issue then we might be able to fix it.