steps to reproduce:
1.
USER1@domain1.com, create a calendar on the zimbra instance running at domain1.com, add any number of appointments
2.
USER2@domain2.com, create a calendar on a second/separate zimbra instance running on domain2.com, add any number of appointments
3. have USER2 invite USER1 on any number of appointments
4. have USER1 accept all the invites, those appointments now appear on USER1's calendar
4. have USER2 share its calendar with USER1 as an external guests (since they are running on separate instances, this is the only way to share calendars)
5. have USER1 subcribe to the remote calendar of USER2
6. all appointments that USER1 was invited to by USER2, now dissapear from their local calendar and are only available on the remote calendar
7. have USER1 delete the remote calendar share, and now all accepted invite appointments now are gone!
i'm guessing when you subscribe to a remote calendar and zimbra sees that there are the same appointments on the remote calendar as the local one, it removes them from the local calendar in an attempt to remove duplicates?
either way, this is data loss on one of my users parts, and it would be best if this can be filed as a bug and get fixed in a future release.
anyone else can verify this?