Calendar entries sending out notifications on shared calendars (again)

I have a MBP and many iDevices. My wife and I share some calendars. About 6 months ago every time one of us added or edited an entry on one of our shared calendars, the other received a notification. It went away in a few days.

Now it is happening again. I think this is an issue on Apple's servers.

Is anyone else experiencing this?

Bryan