Some further info, having experimented a little I can see that I get the same DWORDS errors when the engine uses DX12 without ray tracing, but it doesn’t crash when opening a tab or windows that contains a viewport/3D preview.
Also I can see that ray tracing is in fact working properly before the editor crashes. If I don’t open a tab that contains a 3d preview window or viewport I can look around the scene, change materials and so on.