Hi Martin,
I'm afraid I'm not exactly sure what you mean with "bumped up on SPF_DKIM_DMARC enabled recipients"? I'm not aware of any issues with my MTA, this list is the only place where I have troubles.
IMHO the topicbox.com MX has to be considered broken, because it clearly accepts my mails without error, doesn't send anything back, but still does not feed it into the list but instead it seems to go to /dev/null.
Regards,
Simon
