PROBLEM WITH DUPLICATE CALENDAR ITEMS (THOUSANDS FOR ONE SPECIFIC MEETING)

UNUSUAL ISSUE  

I have an issue where a single calendar event had duplicated itself thousands of times on my for Outlook for Mac (v16.63).  Manually deleting more than one at a time balloons and crashes outlook. 

There are also 6,697 meeting reminder for this meeting.  Clicking on "Dismissing All" simply brings up the balloon and crashes Outlook.  

Other info:

* The invitee had cancelled the meeting (looks like a google calendar), so no longer appears in online version of office, no longer appears on the google account either

* Meeting removed in online version

* Meeting is also duplicated 

Thanks in advance!