Using DataSprings version for ...DNN43PLUS.ZIP on 4.3.6 DNN installation...

I have the "User can change their username" option UNCHECKED in the General Settings.  I am signed in as the administrative user.  When I go in to edit the account, I see that I can enter anything I want in the User name field.  When I click save a NEW user is entered into the database with the new username I typed in.  My original record is intact, but the problem is another user is created.  Shouldn't the Username field be read only when I am attempting to update my user account?

It appears that the problem only exists with superuser or admin accounts.  Regular users have the textbox for their username grayed out.  So apparently the bug here is that the admin or super user can try to change their name, but when the system goes to process it, it thinks a NEW record is being created.  I'm imagining that this is because Dynamic Registration uses the Username as the key field for users.  It makes sense that you should turn off the ability for admins or superusers to not be able to edit their usernames unless you can find some other key to keep DNN users and Dynamic Registration in sync.