I use Sender-dependent transports, and route all outgoing emails through Mailgun SMTP.
Configured according to https://docs.mailcow.email/manual-guides/Postfix/u_e-postfix-relayhost/
Everything works perfectly, apart from the bounces.
So when a user, sends email to a wrong mailbox, there is no bounce-back mails returning.
I understand that mailgun accepts the email successfully according to logs, but then fails to deliver, and adding it to bounces:

And postfix logs:

How to overcome this limitation? Any suggestions