Bump. This issue is still there.
Did I make it clear what the
problem is? Here's an example. The 2 threads below both have 14 replies
plus the original post, so 15 posts in total. 7 on page 1, 7 on page 2, and
the last one on page 3. In the forum index it shows as:

The only way to read the last post is to go to
page 2 and click "Next" or "3":

It is confusing when you don't know about this problem, you'd just
click page 2 on the forum index and read the last post on that page,
assuming it's the last one, and not see the last reply on page 3.
I would say the bug is on the forum index page, it uses "number of
replies divided by 7 rounded up" to calculate the number of page links to
display, rather than "total number of posts divided by 7 rounded up".