RSVP response creates bounce invitation

After I upgraded from 10 to 11.0.1201 (c416881), and with this changed my Office365 account from EWS to GraphAPI, RSVP behavior is broken:

  • I receive a meeting invitation, and confirm that directly from the mail
  • Instead of just sending a confirmation to the meeting organizer, EM Client sends out a new meeting invitation to all invitees with me appearing as the organizer

Expected behavior is EM client sending a confirmation to the meeting organizer, save the meeting to my calendar and mark it as confirmed by me.