Let's clarify something here. Mastodon follower only posts don't have the "public pseudo user" addressed, do they? That's the important piece that this whole thing hinges upon If it is present, Mastodon is a fault. If not, Pixelfed messed up. No?

@mario@hub.somaton.com thanks, I tested that payload and it successfully edited the post, so at least from the payload point of view there is no issue. Perhaps there is a problem with the http signature on update? Is that handled differently than a create?