This bug is a bit weird, the first time path tracing is enabled, I get a message to fix all compile errors in PathTracingMain.

I could repro on v10.2 (and master) with these steps :

make a new HDRP template project
create a new basic outdoors sceene (File -> New Scene)
switch API to DX12
After editor restart, open the HDRP wizard and click fix on all ray tracing related errors.
Add path tracing overide in the scene and enable path tracing

Result : black screen and error message in the console. See screenshot:
https://ibb.co/Gc32Khr

It can be fixed by just triggering a compilation in the PathTracingMain file (with a dummy change).