I made some more experiments and I think Im getting closer to the problem (maybe its only in my project) but usually I use Ultra Dynamic Skies for my projects. And seems without it scenes are fine.
Next experiments showed that Ultra Dynamic Skies itself is okay, but Ultra Dynamic Weather is causing problems - after 1 second after import weather - crash. But it all working okay with RTX translucency - only I turn on Raster - crash.
Further experiments - seems rain causing problems (maybe other effects too but rain 100%). I tried to just put a rain niagara effects - crash, so seems problem in particles and Raster translcuecny interaction((
There is a ue5.2 release in preview - somebody tested it? It will help?