Noone wants to take a guess? I've tried laborating with php's own cache control also adding no-cache headers in the headers with html. No difference...
--------------- Added [DATE]1324416053[/DATE] at [TIME]1324416053[/TIME] ---------------
Some more info.
If I logout and the redirect goes outside of the forum, for example my startpage at root (/). The headers stays as if I am still logged in.
But if I logout, and is returned back to somewhere inside the forum bounds, the headers are not cached and I am really logged out.
Remember, I am including the global.php file, and I am also making use of the global $header variable. This variable seem to be cached and not re-generated when outside of the forum.
I hope someone here knows how to deal with this.