From my understanding (I could be somewhat off here), it occurs because each component in a landscape is its own object in the engine’s eyes. Because locations are stored as floating-point numbers, which are inherently inaccurate in binary, each component may be at a very (and I’m talking very) slightly different height than the last, and when a corner comes into contact with a component of a higher height, it has nowhere to go, causing the jump.
I’m probably not as much help for the solution, however. People on the forum have mentioned changing the track collisions to horizontal capsules has worked well, and there unfortunately still isn’t an official suspension system out from the team. I agree, it really should be taken care of soon.