That is the problem ( very similar if not the same ) I am having after updating from preview 4 , it was fine in there , but in the newer versions the planar reflections are pretty much there except it looks broken and makes the object look pretty dark , posted it on facebook as well , but I don’t think anyone will help since it’s a new feature and there is no documentation , still it seems to be easy to use feature and doing nothing wrong , just the update broke it for me .