RHI QMetalRoughMaterial roughness parameter issue with QEnvironmentLight

In QMetalRoughMaterial the roughness parameter has no effect when using QEnvironmentLight and the RHI. I have tried it with the "opengl", "vulkan", and "d3d11" backends for the RHI, they all have the same issue.  If I define "DEBUG_SPECULAR_LODS" in the  "metalrough.inc.frag" shader code it does show that different roughness values pick different values for "lod", but the  "textureLod(envLight_specular, l, lod).rgb" call seems to yield the same result regardless of the "lod" value handed to it.

If I switch from the RHI to the non-RHI desktop OpenGL backend, the roughness works as expected.