So, after applying the patch, results are mixed.
Things one should know reading the rest of this:
I create users like lms048@domain.com and lmst01@domain.com etc.
They get an email alias like j.m.visser@domain.com and t.account@domain.com
AD properties are populated to reflect the alias as the primary email and things like Fisrt name, last name, etc. are filled correctly.
Email clients are configured on the alias, using username lmst01 to acces the mailbox t.account@domain.com
In all clients, the @domain.com part is dropped from the username while logging on or setting credentials.
First annoyance is to be expected in my setup: (Sending mail)

Mailheader when sending mail from SOGo is correct.
EAX works as expected, including the mail header being wrong compared to how the return address is set in SOGo:
X-Spam-Status: No, score=-100.0, required= 4.0
X-MS-Exchange-Organization-PCL: 0
X-MS-Exchange-Organization-SCL: 0
X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) * on
otherserver.otherdomain.net * at Fri, 24 Nov 2017 07:47:37 +0100
X-Spam-Status: No, score=-100.0, hits=-100.0, required= 8, autolearn=disabled,
shortcircuit=USER_IN_WHITELIST (ham)
X-Spam-Report: * -0.0 SHORTCIRCUIT No description available.
* -100 USER_IN_WHITELIST From: address is in the user's white-list
X-Process: ESTProcessDone
Received: from myserver.domain.com (172.16.1.12) by
remote.someotherdomain.net (192.168.50.2) with Microsoft SMTP Server id
8.3.485.1; Fri, 24 Nov 2017 08:33:49 +0100
Received: from myserver.domain.com (localhost [127.0.0.1]) by
myserver.domain.com (Postfix) with ESMTP id 3B96B180336F5 for
<jeroenvisser@someotherdomain.net>; Fri, 24 Nov 2017 08:33:49 +0100 (CET)
Received: from localhost (localhost [127.0.0.1]) by myserver.domain.com
(Postfix) with ESMTP for <jeroenvisser@someotherdomain.net>; Fri, 24 Nov 2017
08:33:49 +0100 (CET)
From: Jeroen Visser <j.m.visser@domain.com>
To: <jeroenvisser@someotherdomain.net>
Subject: EAXtest
Date: Fri, 24 Nov 2017 08:33:57 +0100
Message-ID: <000201d364f6$96c12890$c44379b0$@domain.com>
MIME-Version: 1.0
Content-Type: multipart/alternative;
boundary="----=_NextPart_000_0003_01D364FE.F885DEB0"
X-Mailer: Microsoft Outlook 16.0
Thread-Index: AdNk9pUQ8kYxJdosSoizqRE9JXLT+A==
Content-Language: nl
>>>>> Return-Path: lms048@domain.com <<<<<<
X-Antivirus: avast! (VPS 171123-2, 23-11-2017), Inbound message
X-Antivirus-Status: Clean
IMAP works as expected, correct headers for my use-case and correctly displayed for common use-case, but not for mine 

But, and that is what this was about;
Note that for some reason, the first picture in this post has me looking up a user and it displays the accountname (my situation is weird, granted)
But I would expect that to be consistent … note this last pic displaying the users who have rights on this mailbox. This is mailbox j.m.visser@domain.com user lms048@domain.com
When looking for the Test Account user, it displays … the alias … as I would like … ehr ??
Rights are not correctly set in my scenario:

Manually setting rights to lmst01@domain.com works, as expected.
Strange behaviours:
- EAX return address in the email header is wrong
- Looking for user in SOGo when SENDING mail yields primary email addres (username in my case)
- Looking for user in SOGo when SETTING ACL’s yields alias email which has been set throughout SOGo settings like below: