Odd RT point light behaviour with DX12 (4.26)

Hi, I am experiencing very odd behaviour in UE 4.26 with ray tracing when directx12 enabled. Let me show it with some images.
I enabled ray tracing and created extremely bright, red, point light and completely closed it off with walls. Except 1 side, I left very narrow area where light can leak on to some object.
Here the first image is just shows the scene:

Now second image is just close up screenshot with:


enabled in DefaultEngine.ini file:

And now last picture without DefaultGraphicsRHI_DX12 option (either when it is just deleted or replaced with DefaultGraphicsRHI_DX11):

Second picture has higher visual quality but it is not correct, it need to look like 3rd picture.
3rd picture looks correct but has way lower visual quality.

I am using rtx 2070super with intel cascade lake xeon processor. Windows 10 Build 19044.2364

Can someone englihten me? Does anyone have any idea about this problem?