Having this problem with my N8:
I thought I might give it a reboot to free up some memory space and upon reboot, my widgets was starting to behave funny. Meminfo was showing 0MB free everywhere and the Social Networks / Communities widget was not connecting to Facebook. Battery widget from Nokia just says "Calculating" and does not load anything.
Trying to load Facebook app says "Sorry, please uninstall and reinstall communities".
Anyone else having this same issue? It doesnt affect all widgets - some other widgets like emails and SPB Weather still works fine.