What is this error and how to fix?

[Google Calendar] Uploading event ‘pay note’ on 1/9/2023 9:00:00 AM to calendar ‘j******@gmail.com/Calendar’ failed due to the following error: Invalid sequence value. The specified sequence number is below the current sequence number of the resource. Re-fetch the resource and use its sequence number on the following request.

Something you can try: right-click on the Gmail Calendar folder and choose Properties > Repair > Repair.

Tried that once and it came right back. Will try again. Any other ideas?