rhi settings bug

there seems to be a bug in the RHI settings. when I have dx12 RHI enabled an error comes up after a few minutes of work that closes the unreal engine and a message comes up that says my GPU has crashed or been disconnected. My Gpu supports DXR & when I have the same settings in unreal editor 4.25.4 with the older GPU light mass it runs without any problems.
I also tried to see if I could export the GPU light mass plugin from 4.26 to 4.25 but it didn’t work.

Could someone see if there is a way to fix the RHI problem. I also tried with TDR modification but with no success