I don't really know what the cause is but suddenly this void started to cover my screen. I am still able to interact with everything in the game world and open up menus fine. It persists through loading old saves but is seems like relaunching fixes it so its not that game breaking, just thought I should still report it. I have linked a clip of it happening below.
ClipThe low fps is because of the clipping software not the bug
It has happened to me once in my time playing patch 8 during the fight with the drow in the goblin camp and once with patch 9 after leaving the owlbear cave.