Signature Variable - System Default Being Used Instead of the Override (Advanced Settings of an Email)

Your software
My Mautic version is: 4.1.2
My PHP version is: 7.4.30

Your problem
My problem is:
When creating a segment email that contains the {signature} variable, the signature that is stamped in each email is the system default. When I add an existing user into the Advanced settings of the email (see screenshot), I thought this would dynamically update the signature variable to the user mentioned (similar to the “Use owner as mailer” option).

The name and email address override works, just not the signature, even when the user exists in our instance.

Is there an existing fix for this, or is this default behaviour right now?

I don’t think this is how it’s supposed to work, unfortunately. When you fill in this from name and email address, I don’t think it knows or cares if that’s a mautic user for any reason.