Calendar/Mail keeps sending updates every 2-3 seconds
When I create a new event in the Mac Calendar and add an invitee/s, the people that I add are bombarded with event updates every 3 seconds. I see that in the sent items in the Mail app - an email every 2-3 seconds.
This means I can't create events! The people I invite are "spammed" by hundreds of email updates.
Needless to say, I made no changes to the event.
When I close the Mail app, those emails stop coming but as soon as I open the Mail app, the sending begins again. The only way to stop is delete the event or delete the invitees from the event.
The account is a Gmail account. If I create the event in the Gmail web interface, all is good.
Anyone?
MacBook Pro TouchBar and Touch ID, macOS High Sierra (10.13.1)