Could be the server. If it's under heavy load (wait, this is GAF, it's under constant heavy load), things like this might happen. It's like asking a worker bee to make copies, fetch coffee, man the switchboard of your Fortune 50 firm's headquarters, monitor where your employees are web surfing in real time, and file his TPS reports - all at once.
Things will slip, especially when other crap like losing Internet traffic packets gets thrown into the mix.