eccube.event.front.response:
    - [trackingCode, NORMAL]

    public function trackingCode(FilterResponseEvent $event)
    {
      $app = $this->app;
      
      ...

    public function trackingCode(FilterResponseEvent $event)
    {
      // 退会時はスキップ
      $request = $event->getRequest();
      $route = $request->attributes->get('_route');
      if ($route == 'logout' || $route == 'mypage_withdraw') {
          return;
      }

      $app = $this->app;
      
      ...