Change User From Administrator To Editor

I have a website at website.tld

John has a website at john.website.tld

I want to change user John from an Administrator of john.website.tld to an Editor.

In Super admin, I edit user John and change the Role from Administrator to Editor and save.

However, John remains an Administrator!

(John is the only user of john.website.tld. Perhaps there always has to be at least one Administrator?)