That link isnt logging you out because its the https address. You must still be getting some of the http address in a bookmark or when you are typing it in to get logged out.
Started about 3 weeks ago when others were having the same problem. I use internet explorer. Cookies are enabled.
If your referring to the link you responded to Fuelrod, that one does not work when I click on it. I'm using an iPad and a desktop with Microsoft and both dont let me stay logged in. Even with the https: Maybe the browsers...?
If that works without logging you out that means you are still going to the http site when you get logged out. Check your bookmarks again, delete fhc from your history if you have to.