I have several truly ancient, long-abandoned servers that are showing up on Managed User’s server selection screens. I have already removed/unclaimed these servers from the main account, but for managed users they remain options with no way to remove them.
Related issue: Old plex servers showing in shared users/managed users, can't remove
I suspect this also holds for all the users with whom I have shared access, as they show as having e.g. 12 shared libraries when I have 6 and the old server likewise had 6…