Code in INSERT CODE BLOCK double space-s after editing. This used to happen if you opened the thread. Now it happens also when you are answering a thread.
Example: http://social.msdn.microsoft.com/Forums/en/transactsql/thread/0a01fe8a-7057-48f6-8ecf-cde568509d62
This is a known issue, we have a bug on this. I'm not sure when we will get to fixing it though, it may be a while, but we are aware of this.