New topics can not be seen by guest

Forum has been inactive for a while. Originally imported from phpBB. New user registers, I get email, approve post, reply to post, all looks fine.

Then I open another web browser that is not logged into the website and browse the forums, those two new posts do not show up.

Go back to the browser that is logged in as admin, the posts are there.

Back to the browser that is not logged in, posts are still missing.

Why would those new posts not show up and how do I fix that?

The page I need help with: [log in to see the link]