Appreciate the level-headed reply in this thread. There's a lot of fingerpointing and hostility going on and I'd appreciate it if people would make less assumptions / jumps to attack people. I'm not sure if you or anyone else can confirm, but I agree with ernest that federation of mod actions was working once before. Without knowing exactly why it stopped, it's hard to say what is going on.
For instance, I just coordinated with the admins of startrek.website as their latest maintenance started blocking user agents with curl
in it, which is what kbin sends, meaning all kbin instances stopped being able to get images from their instance. It seems like this is true for multiple other lemmy instances. I didn't follow up with any other admins at the moment, but I think from that, and the fact that back when I originally signed up people would constantly complain kbin federation was broken when it was lemmy.ml that was blocking kbin, it's not a good idea to jump to assumptions on why something isn't working.
I don't want to give false information, but on fedia the majority of 500 pages seemed to stem from the image media cache causing issues (our instance admin detailed the issue here). People were able to mitigate it by disabling images everywhere they could, but one place they can't be disabled is the user avatars on the notification page. I could be wrong, but it's my belief it's those images causing the 500s, and that pushed me to add https://codeberg.org/Kbin/kbin-core/issues/1039 in hopes that if it was possible to disable them the 500s would stop. All this could be wrong though, maybe it's something else like deleted messages or anything else, or maybe there's a better way to solve issues with cached images