Landscape spline tool messing up my vehicle physics

I created a road path using landscape editor spline tool. But when i drive my vehicle, it bounces when the speed increased. It looks like the physic of my vehicle is mess up when driving on the spline tools generated road. You can see video 1 for reference.

Below is the video of my vehicle driving on terrain with no spline tool generated road. There’s no bounce

Appreciate if someone can share solution to this problem. Thanks in advance!

Did you ever find a solution for this