Mautic 'send from' address only valid if on installation domain?

OK; I’ve dived deep into this and I can confirm with 100% certainty that external e-mail addresses i.e. ones not at @mauticinstallation.com, when assigned to e-mails, are IGNORED and mautic uses the DEFAULT address instead.

Now, that’s a Big Bummer.

Also, there is NO WAY to make Mautic not use the ‘append +_bounceXYZ’ into the source e-mail making any responses fail to be delivered 100% if your SMTP server does not support the ‘+’ semantics.

That should be in red all over the place.

Same problem is visible here:

Currently, there is no way to:

  1. send emails from external domains
  2. override Mautic messing with the source e-mail address.
    Yes, in some cases, especially when sending private e-mails we do not care about tracking at all.