I'm still experiencing a milder form of this problem. My Facebook News Feed updates in Digsby for a period of time - on the order of a couple of hours - and then stops doing so (no error message or other obvious cues).
Restarting Disgby reconnects to Facebook and get the latest news. Of course, if you have to go to the Facebook website to see whether you have to restart Digsby, it does kind of defeat the purpose...
Maybe, if the configuration on the Facebook side keeps changing and messing with the Digsby developers' code, an option to think about would be a "reset this connection" option in the context menu for Facebook (or Twitter, etc. for that matter) on the Buddy List?