If I read a post and then go back to the forum the thread/post is not being marked as read and I have to manually 'marked all posts as read'. Any reason why this is not working?
No one is "blaming the browser". The site knows what threads have you have read (when signed in), the browser does not simply because it can (and does) use cache -- that is what it is for. This is standard-operation-procedure and very much expected when you click the back arrow in most standard browsers.