I noticed something similar on Nordschleife at the weekend - it seems to have gone away now, although I have changed a few CSP settings in the meantime - perhaps post your software and hardware specs so it can be narrowed down a bit...
Yep I'm also on an AMD GPU with a Quest 2, although I'm using OpenVR mode - I'll check the settings I changed as haven't noticed it lately, 'Smart Shadows' in CSP may have been one I switched off...