Hi Victor,
we've seen similar behaviour, and it's mostly caused by the organizer not being set correctly by the interface:
1) User A organizes an appointment in Exchange, invites user B, but does not track the appointment themself.
2) User B accepts the appointment, then tracks it from their end.
3) Appointment will show up in D365, but Owner and Organizer will be set to User B, when Organizer should be set to User A
4) Looping updates will occur. Usually this also means that Exchange will send out new invites over and over again.
What we found to work as a quick fix is to set the appointment to Closed / Completed within D365 - this does not affect the appointment in Exchange, but should exclude the appointment from further sync attempts - however we've also had cases were this didn't help.
The whole "tracking user is set as organizer" is appearing and disappearing from our environments at random, we've observed this changing midweek as well as on weekends, so far Microsoft Support was unable to explain this at all.
Right now it's "fixed" for us, but since MS is unable to explain any of the behaviour changes we're just waiting for this to change yet again.
