I googled a bit but could not find a description or explanation of the problem I observe:
We’re using NextCloud 18 for calendar (CalDAV) and a current Thunderbird for eMail. The NextCloud calendars are configured as CalDAV calendars in Lightning.
Another party is sending us event invitations from MS Outlook / Exchange.
Accepting the invitation works fine. Also forwarding the invitation mail to another user of our NextCloud works fine.
However the direct receipient or the user the invitation was forwarded to accept the invitation, no confirmation mail appears to be sent (I even checked the mail relay logs) out to the originating Exchange system.
I would strongly expect that both invitation accepts (of the original receipient and of the second user in this NextCloud instance to whom the invitation was forwarded) would trigger a confirmation mail to the inviter.
Does anyone else here experience this or is even able to explain what’s going wrong?