Might relate to MC-206460.

The bug

Most doors have birghter pixels at the top and leftmost edges of the texture, and darker pixels on the bottom and rightmost regions of the texture, as to emulate directional lighting. Bamboo doors, however, have neutral pixels at all four edges of the texture, unlike all other doors.

How to fix

Either change the bamboo door shading to add this effect, or redo the other doors to remove it (would bring them more in line with trapdoors).