Short version, you may want to set up a local mail filter to hide messages from this list with that subject.

Unfortunately the interactions between mailing lists and autoresponders aren't very well standardized. The list messages have a List-Id: header which the user agent should use as an indication not to send an autoresponse, but that's apparently being ignored in this case. On the flip side, a proper vacation autoresponse should set a header which the mailing list software should use to discard it, but that also doesn't necessarily happen.

https://datatracker.ietf.org/doc/html/rfc3834 defines the Auto-Submitted: field, there's obsolescent versions such as Precedence: bulk, and many more variants such as these: https://www.arp242.net/autoreply.html. As far as I can tell the mailing list doesn't use any of them, but it's unclear if it would help since mail clients aren't necessarily going to respect them.