Try
r.LumenScene.Radiosity.HemisphereProbeResolution 32
99% of the time this clears it up for a not huge perf impact, default value is 4 so anything above should give a better result.
Try
r.LumenScene.Radiosity.HemisphereProbeResolution 32
99% of the time this clears it up for a not huge perf impact, default value is 4 so anything above should give a better result.