Name change on Domain Alias for all alternatives

Wookimonsta

Hi,
I have a mailcow running and recently added an old domain as a domain alias.
Mostly everything worked fine, but I have an issue when sending an email.

Imagine the mailbox is called microsoft and the domains are domainA.net and domainB.net (the Alias).
I get the following possiblities for sending a mail:

microsoft@domainA.net <microsoft@domainA.net>
microsoft@domainA.net <microsoft@domainB.net>

So I wanted to change the name to something more legible, so I set it to MYNAME via SOGO: Settings -> Email -> Imap -> Edit Identity. Now I get:

MYNAME <microsoft@domainA.net>
microsoft@domainA.net <microsoft@domainB.net>

Then, when I go to the Admin panel and set a Fullname MYNAME2 I get:

MYNAME <microsoft@domainA.net>
MYNAME2 <microsoft@domainB.net>

Are there in fact two identities? Am I doing something wrong?