Interesting. I’m not managing to replicate this, but without DiffuseIndirect, most of the indirect lighting contribution is likely from the SkyLight. Setting intensity to zero seems to create similar visuals to the screenshots you attached. More so than disabling DiffuseIndirect would have.
I would have imagined that the issue would be visible on all settings to an extent as SkyLight contribution isn’t replaced, but does manually disabling the skylight in editor seem to replicate the issue on Low and Medium?
Best regards,
Chris