Shading of certain directional blocks like beds and chests independent of normal blocks

The bug

Blocks like chests and beds do not adjust their shading in different orientations, so the front and back of chests and the short sides of beds are always brighter, no matter wether they face North/South or East/West.

It also seems like the brighter sides of these blocks are just as bright as the top rather than slightly darker (stone blocks for reference).