Forum indicators vs Messages

In the high level view, where I see the forum names and those little noticebosrd icons to show if there are new posts, I see the flags showing if a forum has new posts.
There are two pieces of paper on the noticeboard instead of one and the forum hyperlink is orange.

BUT when I click on the forum and look at hte messages, none of them are flagged as new messages.

This happens when I log in for the first time in the day - it's not a problem with being logged in overnight or anything like that :(

This is my problem exactly. I have FF clear all history when I log off...

Now that I think about it this happens to me. If I am at the site a lot there will be the icon for new posts, but when I check it they are the same posts as before with nothing new. I don't think it is a firefox only problem, because my computer at work does the same thing and it uses IE.

Z