Is this still an issue? I have just noticed that non of the sidebar widgets display to anon users.
Edit- nvm i think it is a theme issue.
I noticed that on this site sometimes if I view a topic and then click the browser's (chrome) back button to go back to the category page, the list of topics doesn't show up on that category page. I still see all the stuff surround ingit like the New Topic button but the list of topics itself is not there anymore.
Can you reproduce this reliably anywhere?