Hmm... looking at their instance list and stuff, I get the feeling they might consider fedia an "inactive" instance (based on the information being out of date), which is a bug lemmy has where after upgrades it marks instances as inactive and never updates it again. I will try to get in contact with their admins to confirm
Edit: quick edit, speaking with another german instance owner they said they have the same problem with feddit.de right now and have already spoken to the admins and already taken steps to reset active state but it isn't happening, perhaps more debugging is needed or maybe this is the lemmy federation issue people have been discussing