The combination of RTGI + HDRIBackdrop(I have my skylight set to static) seems to be broken? "RTGI Only" looks correct, you can compare that to the path tracer reference. I do have "r.RayTracing.GlobalIllumination.EvalSkylight" set to 1.

On a different note, I'd like to thank the developers for improving the performance and quality of the RTGI!