I remember there were questions about forums pages that don't update automaticaly. When you visit any topic and then come back to the page you came from, for example main forum page, you see it as it was before even if there were posted new messages. The page don't refresh until you do it by yourself.
I have a clue now. Since I'm at my new work I noticed that browser properties, which force browser to use proxy server, are set. It means that pages are cached and then when you visit it again it loads from the proxy server not from dmbeatles.com.
But proxy servers are all different so it all depends on proxy settings...