We saw this over the past couple weeks. It freaked me out and google's g suite support was useless. I did report the IAM it looked like these invites came from (to both the cloud fraud form and gsuite support) but maybe that listed IAM is actually google's auto-add-to-calendar bot? I didn't think it made sense to contact cloud enterprise support which tends to have awesome responses.
I was concerned because:
* we received more sophisticated than usual SPAM/phishing to our employees 'from' one of our partners around the same time
* we work in politics
* the timezone on the calendar spam was Russia and multiple staff received the spam invites
I was concerned because: