Session not saving.

When I fire an event and broadcast event in redis, the flash messages are not saving, but If there's no event the flash message is saved.

BROADCAST_DRIVER=redis
CACHE_DRIVER=memcached
SESSION_DRIVER=memcached

My controller

if ($isEmployee)
    {
        event(new AccountUpdated($data));
    }


  Session::flash('notification', 'Account has been updated.');

  return redirect()->back();