I have seen similar behavior from other
VB sites and assumed it was the same, i.e. phantom pages but no actual additional posts (so nobody is really missing anything, it's just a pagination error). In that case, we'd just live with it, because as you say, no big deal.
But some members have reported that there are in fact posts that have been made on the phantom pages that can't be seen (how they would know that is still not clear to me...), so I'm continuing to investigate.