I have seen this twice now but probably has happened more and just not been reported. It seems at times you log out of the site and then the CSS for the home page; and maybe other pages but since the login is at the home page..., will not load in resulting in a huge mess of a page. Clearing all the caches fixes the issue so I guess I will turn off CSS caching. Seems the Dolphin cache engine has a lot of issues and I often see as an answer, "Turn off xxx cache, clear caches and reload..."