June 09, 2015
So this happened a few minutes ago:
(link to image, link expires in a few days)
https://www.dropbox.com/s/82v2hpod32h5i7y/bug.png?dl=0

My comment on the thread was the 4th post, I wasn't the OP.
June 09, 2015
On Tuesday, 9 June 2015 at 02:11:07 UTC, Kyoji Klyden wrote:
> So this happened a few minutes ago:
> (link to image, link expires in a few days)
> https://www.dropbox.com/s/82v2hpod32h5i7y/bug.png?dl=0
>
> My comment on the thread was the 4th post, I wasn't the OP.

This is a known issue, and occurs when a mailing list user replies to a mailing list user. Because Mailman mangles message IDs, the second message references a message ID that the forum doesn't know about, so it appears as a new thread.