It's a known bug with Facebook - just started up recently.
No one knows why it's doing that, but we're pretty sure it's on the Facebook side (most Facebook apps are having this trouble).
Best solution is to go to Facebook via the web browser (if you don't want to fiddle with getting the app to load).
And, we don't know when it'll get fixed (or even if Facebook is working on a fix ... or aware of it).
Marilyn