A tutorial about Ion Auth and authentication in CI3

i have dig a little and session are working, it's only the ion auth wich is losing data
when i do this on the login page all those var are still present on other page, at the contrary for the ion auth session, [identity] => admin@admin.com desapear when moving from page to page, like if this variable was destroy somewhere in the process

PHP Code:

        if ($this->agent->is_browser()){$agent = $this->agent->browser().' '.$this->agent->version();}
        elseif ($this->agent->is_robot()){$agent = $this->agent->robot();}
        elseif ($this->agent->is_mobile()){$agent = $this->agent->mobile();}
        else{$agent = 'Unidentified User Agent';}
        $sessionData = array(
            'session'    => time(),
            'agent'      => $agent,
            'full_agent' => $this->agent->agent_string(),
            'lang'       => $this->agent->accept_lang(),
            'language'   => $this->agent->languages(),
            'referrer'   => $this->agent->referrer(),
        );
        $this->session->set_userdata('user',$sessionData);