Freron MailMate

I am using Microsoft Exchange in IMAP configuration and for every mail I send there will be two entries in the Sent Items folder.

It seems to be because MS exchange adds its own copy. Is there a way to avoid this behaviour?

--Olaf

Below is a diff between two mails that are stored with email addresses redacted.

diff -u  1052935.eml 1052950.eml 
--- 1052935.eml 2018-10-08 11:21:21.000000000 +0200
+++ 1052950.eml 2018-10-08 11:22:05.000000000 +0200
@@ -1,19 +1,37 @@
+Received: from [192.168.178.22] (2603:10a6:200:68::18) by
+ BN6PR06MB2721.namprd06.prod.outlook.com (2603:10b6:404:5e::11) with Microsoft
+ SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id
+ 15.20.1207.26 via Mailbox Transport; Mon, 8 Oct 2018 09:21:26 +0000
 From: "Olaf Kolkman" <REDACTED>
 To: REDACTED
 Subject: TEST MAIL
 Date: Mon, 08 Oct 2018 11:21:21 +0200
 X-Mailer: MailMate (1.12r5523)
 Message-ID: <5FD21135-91C9-4D56-8ED6-78CE7FB667C8@isoc.org>
-MIME-Version: 1.0
 Content-Type: multipart/alternative;
  boundary="=_MailMate_673F8C34-87FD-4B5F-8A71-93F3C19B6DB7_="
-
+X-MS-Exchange-Organization-ExpirationStartTime: 08 Oct 2018 09:21:27.0334
+ (UTC)
+X-MS-Exchange-Organization-ExpirationStartTimeReason: Original Submit
+X-MS-Exchange-Organization-ExpirationInterval: 2:00:00:00.0000000
+X-MS-Exchange-Organization-ExpirationIntervalReason: Original Submit
+X-MS-Exchange-Organization-Network-Message-Id:
+ 14ce5707-ca44-4170-e1c9-08d62cff6ca1
+X-MS-Exchange-Organization-AuthSource: BN6PR06MB2721.namprd06.prod.outlook.com
+X-MS-Exchange-Organization-AuthAs: Internal
+X-MS-Exchange-Organization-AuthMechanism: 06
+X-Originating-IP: [2001:980:2282:1:340b:f591:d601:7ead]
+X-ClientProxiedBy: AM4PR0501CA0050.eurprd05.prod.outlook.com
+ (2603:10a6:200:68::18) To BN6PR06MB2721.namprd06.prod.outlook.com
+ (2603:10b6:404:5e::11)
+X-MS-Exchange-Organization-MessageDirectionality: Originating
+Return-Path: REDACTED
+MIME-Version: 1.0
 
 --=_MailMate_673F8C34-87FD-4B5F-8A71-93F3C19B6DB7_=
 
 
 
-
 TEST
 --=_MailMate_673F8C34-87FD-4B5F-8A71-93F3C19B6DB7_=
 Content-Type: text/html