Signs Bugging Out

Basically, I was making a Adventure Map, and obviously there were signs for Rules and stuff. I logged into that Map using 1.7.10 by accident, because it should be 1.8 however, when I logged out of 1.7.10 and logged back into 1.8 all my signs had [ " ] at the start of each line, and weird codes and replaced some words on the lines...