This is supposed to be a reply to Topic:Tdlgji9ydqxrj4m4 but I can't figure out how to reply to it. :( It seems that pinging is still broken for me too, so I only just saw your reply...
You did add de-formal in Special:Diff/377029907. Maybe you removed it from your list since then? (Although it's a bit weird if you don't remember doing that :))
I don't think it's a good idea to copy labels that you don't know are correct. It's easy to spread mistakes (or even vandalism) and it's a lot more work to fix later when someone finally spots the mistake.
Some more labels which look dubious to me are all of the Kazakh ones and the Shona one. It doesn't look like you've added any Kazakh ones, but you have added Shona ones. The Shona label appears to be plural and I don't think the capitalisation is right either. I don't speak Kazakh or Shona though, so I'm not completely sure and I definitely can't fix them.
Perhaps it would be a good idea for WikiProject Names to create a list of labels which have been verified and are fine to use in descriptions, and a note of people to inform and tools to update when the list changes. Then you, User:Dereckson, MediaWiki:Gadget-autoEdit.js and anyone else who wants to do something similar can all use the same list, rather than everyone working with separate conflicting lists.