Sign text dissapears when logging off (relogging will fix it for now)

Sign text fails to load on 1.6.2

What I expected to happen was...:
the text appearing on the signs

What actually happened was...:
I logged in in front of a sign witch didn't have the text i wrote on it (singleplayer) it didn't have the text but another sign next to it did have the same text i wrote (i copied them)

Steps to Reproduce:
1. it only happens sometimes when logging on facing the sign
2. it appears to be doing the same with leads witch are blocked by a wall [ can be an animation issue]
3. i cant describe it better sorry for my bad english and good luck fixing it!

have a good day

P.S. i found out that whole block animations arent showing but the grids tells you they are there! ill put a photo about that!