Occam’s razor - you deleted/renamed something you shouldn’t have, resulting in an impossible or dizzyingly loopy schema. Or someone with access to your base did. I’d suggest making a backup, restoring your base to an earlier version which you are certain allowed the use case you’re describing, and compare the two, property by property.
We can speculate here as much as we want but oddities such as this one are a large part of the reason backups exist in the first place; troubleshooting them manually, as you have hopefully realized by now, is a highway to looney land. :grinning_face_with_sweat: