iOS Native Calendar - Reply to Organizer or Attendees

[PaulManson]

I am seeing inconsistent behavior on a feature.  iOS 13.2.3, Exchange 2016, native Mail and Calendar app, ActiveSync configured via Profile.  When opening an event in Calendar, there is supposed to be a little mail icon in the upper right allowing the user to reply to the organizer via email.  Additional, when opening the Invitees screen, there is the same icon to send an email reply to all attendees.  Both are listed in the Apple user guide for Calendar (https://support.apple.com/guide/iphone/send-and-receive-invitations-iph82c5721ca/ios), along with the cryptic ' Not all calendar servers support every feature.'   It appears normally enrolled devices in my environment have neither button.  One person, using ActiveSync outside of Workspace ONE, sees both icons.  I tried on my personal device, also outside of MDM also using just ActiveSync, and I see the icon on the attendee screen, but not event screen.  I have ' Prevent use 3rd Party Apps'  and ' Prevent Mail Drop'  and ' Prevent Moving Messages'  enabled, could this cause a negative interaction between Calendar and Mail?

[PaulManson]

In case anyone comes across this, I opened a support case and they confirmed the behavior.  The setting ' Prevent use in 3rd party apps'  disables this.  The point of it is to block use of alternative mail clients which are out of our control, but has further impact.  When enabled, no application which uses the Share button can then initiate a new email message.  What I learned was this also removes the two Calendar reply buttons I noted.  Making a test profile with that setting disabled returned the functionality.  I would suggest renaming the setting to be more descriptive, adding this information into the quick tip, or at least into the documentation on the setting.