Hello
I saw that when a person deleted its account, anonymity is used instead of their username.
Just so you know (if you didn't already knew), the username is still showing in the select's options (example : https://www.tvmaze.com/shows/6198/le-visiteur-du-futur/edits?Edit%5Bcreator_id%5D=1045&Edit%5Btype%5D=&page=1 )