@girish Yes I definitely do use mailing lists, sorry I thought I noted that before. Many (though I don’t think all) of the email directories that are unexpectedly found in this directory are from mailing list addresses. In other words they are on the recipient list of a mailing list.
So it’s as if the mailing list feature is creating these too, but it doesn’t make sense of course to have one on the forwarding addresses. The mailing list email I could see and understand I guess since it’s still trying to identify spam to not forward, but I don’t get why it’s adding the destination addresses in as if they’re mailboxes that it can learn from.
I can’t reproduce on-demand that I’ve seen so far but just giving it time for a day or two and they’ll start to appear. I guess sending an email to the mailing list would trigger it, I can try that too next time I’m at my computer again.