It will only show upto page 6. As an admin I can see page 7 exists, but it is inaccessible. I've even posted a reply in the hopes of being redirected to it but even that won't work.
As a guest, the forum reports there are only 6 pages - with the last post being Oct 09, though I know I have just posted now (Mar 10).
Initially, I thought it may have been VBSEO causing the issue, so I disabled it. The problem continued. I then disabled my plugin system from within the ACP - and it still continued (while using traditional URL formation as above).