Riva has traditionally synced deleted CRM calendar items to Office 365 and Exchange, which then removed the calendar item from the user's primary calendar and placed it in "Deleted Items". The challenge with handling CRM calendar deletions this way is that users often do not want to lose a calendar item in the mail box, even if it has been removed in the CRM.
There are three reasons that Riva will detect CRM calendar items as being deleted:
Sync Policy Calendar Option
Riva 2.4.32+ includes an option on the sync policy "Calendar" page to control how Riva will handle CRM calendar items that are "deleted".
Effect if Users Have Already Synced Calendar Data
If Riva has already synced calendar data, Riva will not modify calendar items that have already been placed in "Deleted Items". Riva will only apply this change to CRM calendar items that are "deleted" after the sync policy has been changed.