Normal maps seem to be inverted (inside-out) on some block faces. The problem is not in the texture itself, as rotating the block during placement changes which face is affected.
Can be observed on a station or a ship. I tested in single-player mode with an existing build and world, and also with a fresh download and world. I used the latest "pre" build, 20170516_105555, but have no idea when the issue first appeared (not in this build I believe).
For my example screenshots I replaced t001.png in the Default texture pack with a solid gray image, to make the normal map more observable.