On Occasion!: I've noticed when placing signs in any wood type, with text, that after I finish typing and confirming the text box, the UI will drop out like normal, the text on the sign will very briefly flash, but then it will become invisible. If I destroy the sign and try retyping it and going through the placing procedure, the text will again flash on the sign and then disappear. 

This seems to happen more when there are more signs placed instead of just individual signs on their own. I am not using vulgar language on the signs, just very common names. 

So far I've only noticed this issue on a shared realm with 6 players. I have not come across this in single player because I rarely play single player and don't need to place signs with text.