I have just registered and configured two Linux-based systems (both openSUSE Leap 42.3) and have been able to receive notifications about system down/up events as well as notifications about services not being started. This works perfectly well.
What received my attention is that:
* Shutdown notifications are not being sent. I have found out on this forum that this may be caused by the event being sent after the network interface has been taken down, so I am just ignoring it. Nonetheless: can you confirm this behaviour?
* Notifications about user login