Hi macallf,
Whenever LR is suddenly stopping to do things which have worked well before: the usual suspect is the preferences file.
Make that invisible to LR by renaming it or deleting it while LR is closed, so a new one will be created upon next LR launch.
It may cure your phenomenon or may not.
I second Rob that I consider Jeffrey's diligence as a plugin-developer far more superior than Adobe's since LR4.x
Not having used that particular fb plugin of him (nor Adobe's native one), but quite a bunch of other plug-ins from Jeffrey I can state that he delivers on his promises in impeccable quality. Add to that his responsiveness to user inquiries and you have the role model of what Adobe ought to be.
Cornelia