Well, I don't know what to tell you.
I had exactly the same problem with wobbly distant mountains on many tracks including Reboot Fuji (which oddly enough didn't have the issue at all when we made the track a few CSP builds ago...), but weirdly only when looking through the cockpit glass and never in exterior cams.
These clip plane settings fixed it all instantly.
View attachment 1286650
Remember, CSP updates almost always break things that worked perfectly before. We currently have headlights getting turned on in daylight, the hotlap ghost has vanished, windscreens randomly don't allow shadow-casting light through unless you restart the session etc etc etc.
If something suddenly breaks after an update you're often better off just reporting it on the shader patch discord rather than trying to change a setting to fix it, because if the next CSP update fixes it at source, your settings have changed for nothing and might actually bork the fix.
Incredibly frustrating we know, but CSP updates have always been three steps forward and two steps back.