The most common reason for getting a bounce back email message, from an email address that isn’t associated with one of your profiles, is due to someone having email forwarding set up on their inbox. The person likely has some filters or rules set on the inbox that forward mail to the other email address.
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The other alternative is that the email address on one of the profiles is not actually an inbox, but a distribution list, which is pointing to an inbox that doesn’t exist.

Either way, the best route, to prevent these from ending up in your inbox, is to speak to the person about it, and ask them to turn off their forwarding to the inbox that doesn’t exist.