Before I comment on that bug report, I'll try to to gather some more information. What I did now is to switch off anything that fills the feed screen... I'll add feeds and notification back one by one and try to find out if I can identify one that reliably makes this happen.

What's funny is that, although there's only 9 feeds I have subscribed to, the status message indicates that the N9 is trying to download a feed #17 or #18. Doesn't feel right. (Or would that be the 17th item from a feed?)
Also, when I open the RSS application itself, there's no feed that shows any download activity. Manually updating all feeds works fine, is done within a few seconds and doesn't change the status of the "frozen" feed in the status bar at all.