This has to be something with cache control meaning browser caching. I don't think redirect helps. you should disable this and use CodeIgniters Cache Library if any caching is needed.
Add the following to the pages where users are required to be logged in:
//Prevent browsers from using history to browse in the user system. $this->CI->output->set_header("Cache-Control: no-store, no-cache, must-revalidate"); $this->CI->output->set_header("Expires: Sat, 26 Jul 1997 05:00:00 GMT"); $this->CI->output->set_header("Pragma: no-cache");
When pressing back in the browser the page will be refreshed.