The unregistered method on the ionic showcase is connecting directly to the Firebase Cloud Messaging and blocking it to receive message but the devices still in the UnifiedPush Server database. It means it will still be listed in the UnifiedPush Server console and also it will still trying to send message for this device and receiving an error from the FCM

A new method to unregister the devices from UnifiedPush Server need to be added in the AeroGear JS SDK.