What feature did you turn off exactly?
In the default Apple App, the Cc/Bcc line also includes the "From" address. That is the email address you are sending the email from. When collapsed you will normally only see your own address as it is the one you are sending from. It is normal.
You cannot turn this off as its a required piece of information for email messages. They must always have a "From" address.
The Cc/Bcc are additional addresses in that same section, but will almost always be empty unless you enter an address there yourself. No addresses will be added to that automatically unless you select the "Reply to all" option when answering an email message and there are addresses in the CC line from the original email message.