After reading a forum, or specific thread, when I return to the index page it still says there are new posts when there are not. To fix this you have to close your browser, and come back to the site. It's very annoying for myself and my users. Is this a cookie issue?

I have this setup and working fine on my website, minus news actually showing up. I have specified a new forum id I just made with a test post in it, and nothing shows up. Just the welcome message. Anything I'm not doing right?