Sign Blackening (Lighting Problem?) 1.3.2 and 1.4.2

Well, every time I go near or read a sign, different signs are black from different angles, and some are just normal. (Note: The Screenshots in the night were in Multiplayer, and the ones in the day were in Singleplayer, I also tested them in both day and night, same thing.)

What I expected to happen was...:
I expected the signs to be all normal, with their text.

What actually happened was...:
What actually happened was that some of the signs are black, and depending on where I was, the signs were either normal or blackened.

Steps to Reproduce:
1. Open Minecraft 1.3.2/1.4.2
2. Craft or Get a sign.
3. Place or Read the sign.
4. Notice some of the signs are blackened and some are normal.