Comment 12 for bug 1604181

Sorry, I missed your Ubuntu comment the first time. I don't see any patches at http://archive.ubuntu.com/ubuntu/pool/main/m/mailman/mailman_2.1.16-2ubuntu0.1.debian.tar.gz that would affect this.

I can try to duplicate this with the 2.1.16 base, but I have to build it so it won't be right away.

However, I still think it might be something in his original Reply-To: which I haven't yet seen. The message you posted at https://bugs.launchpad.net/mailman/+bug/1604181/comments/8 was sent from "X-Mailer: Microsoft Office Outlook 11" and his list post at https://bugs.launchpad.net/mailman/+bug/1604181/comments/5 was sent from "User-Agent: K-9 Mail for Android"

What does his Reply-To: look like in a message from his phone? If it looks something like

Reply-To: Accessibility, ... <email address hidden>

that could explain this.