I notice this when I cursor around a comment. I'll hit a cursor key several times, but the cursor doesn't move. Suddenly, my keystrokes are processed, and the cursor jumps to where I was trying to go. This doesn't happen all the time, only periodically. (God, I hate it when an error is "intermittent".) From my somewhat limited knowledge, I'm speculating that communication between the browser app and the server may be delayed, resulting in a freeze. Intermittent = difficult to reproduce. Good luck.