Bounced emails not being detected

DMARC alignment fails since the reply_by_email_address is used as the envelope-from address in this situation.

Pretty much the only thing guaranteed to be intact on a bounce is the address.

Maybe the subject, but it would not be practical to put this information there.

I do see that some systems include the original message as an attachment… it’s theoretically possible that we could check bounces for an attachment to get more information if they exist.