The problem you're seeing would be a delay between the change and the CHANGE_NOTIFY reply being put on the network by the server, a delay between the CHANGE_NOTIFY reply being put on the network by the server and being received on the client's adapter, a delay between the reply being received on the adapter and being delivered to a FindFirstChangeNotification()/FindNextChangeNotification() call in Explorer, or between that indication being delivered to the call and Explorer updating the window.