I am working with an internal Outlook/O365 user who is receiving calendar invites from external an Google calendar user. When my internal user receives an invite, an event is added to his calendar. If the Google calendar user updates/changes the event, a new invite is sent to my internal outlook user with the subject "Updated invitation: "
My internal outlook user then sees two events on his calendar. One with the original invite information, and a duplicate event with the subject "Updated invitation: " added to it. I tried to re-create this behavior by sending myself an invite from google but was unable to recreate the issue. My own test results with the original invite being updated. Where my end-user is getting a duplicate invite with a different subject.
Someone else at some-point had this same issue however a solution was never posted: https://answers.microsoft.com/en-us/msoffice/forum/all/outlook-calendar-not-updating-invitations-send/00b2fa14-d214-4f4b-8c9c-daf28f32ebc5
Would love to hear any suggestions/feedback.