strange SMTP interaction with mail.openbsd.org ?

Hi,

Recently we've set up a Postfix mailserver with TLS (valid Let's Encrypt
certificate).

So I was checking the logs and I saw mail.openbsd.org connected and
disconnected but strange enough did not deliver any mail:

Sep  6 21:47:13 mx5 postfix/smtpd[938]: connect from
mail.openbsd.org[199.185.178.25]
Sep  6 21:47:14 mx5 postfix/smtpd[938]: Anonymous TLS connection
established from mail.openbsd.org[199.185.178.25]: TLSv1.2 with cipher
ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)
Sep  6 21:47:15 mx5 postfix/smtpd[938]: disconnect from
mail.openbsd.org[199.185.178.25] ehlo=2 starttls=1 quit=1 commands=4

When I checked on the other server, it seems mail.openbsd.org probably
tried to deliver '20200906194148.GA50189@dalek.home.local'.

The name in the MX-record matches the forward and reverse DNS, the
HELO/EHLO name and certificate.

Any idea what could have happened ?(or maybe how to contact the
person(s) running mail.openbsd.org)

With kind regards,

 Leen.