Seems like a problem with SM6 and DX12. Loaded SM5 + DX11 on UE5.1 without same crash on Octane load.

Also crashing on Existing & New projects with 0.59 build on UE5.1
Octane didnt work on the preview 2 build either.

Windows 10 21H2 64bit (19044.2251) R9 5950x - RTX3090
Tested on latest Studio driver 526.98 and 522.30

UE error code:
Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address ...