Comment 382 for bug 439448

He means that the bug is a known painting issue with gnome-panel, and that no "networking experts" should be looking into this because it is definitely unrelated to networking.

Even the connections you suggest, which are valid hypotheses, are obviously only circumstantially related to networking. Most likely, network-manager is taking either longer or shorter to establish a connection than before, causing nm-applet to update at different times during session start-up, in turn triggering the race condition that causes the corruption more often. It would be equally likely that an update you installed around the same time that you switched routers made the problem worse.