Calendar invitation declines are not send to organizer

When I receive a Calendar invitation (mostly send from other Outlook systems), then I can accept it, etc…and my response is send by emclient to the organizer…
However later on, when I decide to decline it from the agenda view, emclient asks to send a decline to organizer, and when I state YES…nothing will be send to the organizer…(leaving the organizer think that I will attend the meeting)

I recreated this with three GMail accounts:

  1. Outlook setup using POP3 and a local calendar.
  2. eM Client setup using an IMAP account and it’s Google Calendar.
  3. eM Client setup using POP3 and local calendar.

Invitations sent from Outlook are received by eM Client, and acceptance is relayed back to Outlook. However, I can confirm that the decline notice is not received by Outlook from either eM Client setup.

When using local calendars, I noticed that when eM Client initially accepts the invitation, an email is sent to the organizer. If you later change your status to tentative, an email is sent to the organizer after a confirmation window.

But when you later decline to attend, the event is just deleted and no email is sent.