There is a small lighting glitch that occurs when fences are placed on top of blocks with exposed sides where they cast an awkward shadow on the block below them, as shown in the screenshots. It makes using fences for windows a little annoying in particular. Not a major bug but i couldn't find it listed anywhere else. Placing torches nearby or on the darkened surface does not change it, and the shadow is present no matter what block is below the fence when i tested it.