I experienced this on Multiplayer, but still haven't tried if it's a bug on Singleplayer yet. The bug: Sometimes, no matter what the player does, a chunk error may appear close to the player. The chunk error sometimes gets fixed when the player moves in it. Also, when a chunk error appears, there are loads of errors showing up in the chat (pretty annoying): "Unable to locate sign at (x,y,z)" Where x,y,z is changed to an x,y,z coordinate.

Also, sometimes the player gets disconnected from the server because of "Bad compressed file format".

You can basically reproducing all this by making a Bukkit server (though other server softwares might work as well, but I experienced this on Bukkit), and just play around for a bit. Other players I play with experiences the same bugs as I. This is a highly annoying bug and should be fixed soon!