I can't be sure but... were you using Facebook Contact sync via the App and not via Sense? if so Gingerbread removed the ability for Facebook app to sync contacts with Android contacts, something to do with Facebook not allowing contacts to be saved to a csv or something like that. Thsi could have screwed up your contacts when they turned this off. Sense syncing still works though.
Thanks for the tip. To refresh my contacts I thought I might remove my login to Facebook for Sense and log out of the Facebook app. When I logged back in to only Facebook for Sense (only), none of my FB contacts now show up under "People" with their photos. And if I try to "Link" to a contact in FB there are none to choose from.