Good catch ! That was a real bug, the adaptive quality only ran on mobile. Fixed and reuploaded, should be smooth now. Thanks for the dust comment too.
Both real, thank you! and the berm one was a good catch. The collision boxes for the outer berms were being placed with a corrupted direction vector, so all 72 of them ended up about a kilometre off in the grass. The track rendered perfectly and just had nothing solid along the edge. The guardrail posts were going to the same wrong place, which is why they were missing too. Fixed, with a test that raycasts the whole lap and checks what the physics world actually contains rather than trusting the code.
The inner edge is intentionally open. No berm there, just the off-track timer. I'm glad you pushed on it.