Sometimes, whan I join a server, (Now, this is server specific, it might not occur on other servers while occurring on a certain server) I can't see the scoreboard. If the objective that currently has any display gets updated (If the values get updated, this will not happen), it will crash the client. Rejoining or restarting does not help. The only way to get rid of this is by waiting. It might work the next day. I have not had this happen in singleplayer, but I don't play so much of it.
Here is the crash report: http://pastebin.com/aEzQ1ZEL