The code that generates UAVs for 3D textures fails when the Z axis is shorter than the others when generating mips, as it does SizeZ >> MipLevel.
It should be max(SizeZ >> MipLevel,1) instead, otherwise it goes to 0 when SizeZ gets smaller than 2^MipLevel and that makes the UAV creation to fail.
The problem is on line 92 of D3D12UAV.cpp and on line 67 of D3D11UAV.cpp . Haven’t checked the other RHIs.