Even weirder is this post itself. I posted this photo thread once, but two posts appeared in fedia discussions. I then opted to delete one of them, and the delete action on one deleted both of them. So I reposted again using the “add new photo” option, and again it created two threads.

The post in the snapshot was a case where I posted in https://fedia.io/m/Brussels and then posted a link to that thread from a sopuli community. The duplication in that case is apparently due to another anomaly. Or perhaps not.

(edit) interesting to note as well that this comment was not duplicated. So there is a parallel universe but without the contents therein being mirrored.

Also noteworthy: after deleting the thread it became non-existent to me, so I had no way to undelete it. Which means I had to re-upload the image to recreate the thread. Lemmy does better on this… when you delete your own Lemmy thread, you can still undelete it.