This has recently been reported by another user. Is there a chance for your scene, so that we could reproduce it better?
In case of the user user the workaround was to either:
- Disable UHD Cache (switch to PT only, which would obviously increase render times)
or
- Remove translucency from a material, which was occluding a light source
The solution may be switching to the new 4K Cache. The build featuring it should be released soon. In our tests, the 4K Cache did not trigger this issue.
(Internal ID=518735615)