I've been getting the same thing for a few weeks now... I believe it is a Facebook app error. There is a lag with my notifications. I just uploaded the Beta from BB Beta Zone and the same issue still happens.
In addition to my earlier post... I also had this issue on my 9550 prior to getting 9930 about a month ago. So I'm pretty sure this isn't limited to OS7. It's gotta be a FB app error.
I dunno I don't think its just the bold its the Facebook app for blackberry is pretty bad I never seem to get notifications when I receive an inbox.. I always have to check or go on the browser Facebook then it would show that I got a new notification