Fields 'uneditable' after Profile is copied

After making a copy of a Profile, it appears that the individual fields within that Profile become uneditable due to a bug.

For example, I made a copy of a Profile. Then I went into the new Profile and tried to edit one of the fields (the Primary Email field--I tried to change it from not required to required). However, every time I tried to save it, I received the following error: "The field was not added because it already exists in this profile." The attribute I tried to change (make the field required) was not saved.

Hope this helps--again if you need more info or if I'm not putting this in the right place, let me know!