CI3 and HMVC: fetch_module() issue

PHP Code:
Class Start extends MX_Controller
{

    // Some class properties...
    // ...
    
    // $data contains all vars used in template and view files
    $data = [];
    
    public function __construct()
    {
        parent::__construct();

        // Some other code
        // ...
        
        // Navigation & breadcrumb view partials
        $location = array(
                            'active_method' => $this->router->fetch_method(), 
                            'active_class' => $this->router->fetch_class(), 
                            'active_module' => 'start'
        );

        $this->data['topnavigation'] = modules::run('navigation/topnavigation', $location);
        $this->data['breadcrumb'] = modules::run('navigation/breadcrumb', $location);
    }

    
    public function index(){
        die(echo $this->router->fetch_module()); // expecting 'start' BUT returning 'navigation'...
    }
}