I tried the oval and I found 2 serious errors with black holes: one is just at the exit of the pits, if you come out of the pits and turn a little to the left, you have a black hole that, coming from the pits is not a problem but If you have a small accident on the track and go to that area, you are lost.
Another problem is in the outer wall. There is an area that has no wall (I have tried mod cars and Kunos cars and it is the same problem.) I have opened the file collisionoval.kn5 and I have found that there is a piece that has no wall and there the problem:
https://i.imgur.com/9xd2mgp.jpg
https://youtu.be/bvoevfbShI8