I tried updating MC to 14w25b, when my game crashed (see MC-57890), but that's not the point of this post. After that, I returned to 14w21b, and I checked up on some of my signs. Well...you can see for yourself what happened to them. The quotation marks and "null"s shouldn't be there. (Interesting that in the last screen shot the "water" sign didnt get messed up.)