I just checked in and notice within the last couple of hours or so that 76(!) post have suddenly appeared in the review queue for first posts. WTF? I looked at the dates on just a few, and they weren't all recent. Obviously I'm missing something about how the system works or is supposed to work. If anyone knows what's going on and how old posts can suddenly show up in the first posts queue, please explain.
This is the result of a recent bug fix. Apparently there was a bug that prevented some posts from appearing in the queue. Since the bug was fixed, those posts that should have been in the queue now are.