Thanks for the information @Skowroshima and @VintsKlea! It looks like the error is logged and in the issue tracker but has been backlogged. It seems that setting the skylight to movable has been a workaround for some users but obviously incurs some performance problems so may not be ideal. I do recommend submitting supplementary information regarding the bug referencing the issue number UE-116954 so if it can help an engineer solve it when the time comes!