email and last name are set to Username in case "Auto logon for each visit" is checked

Username appears in other field in case "Auto logon for each visit" is checked

How to repeat:
1. Sign in with existing user (user/password)and check "Auto logon for each visit"; save your password in browser
2. logout
3. Click Sign Up and overview the registration form

As a result, email and password fields are filled with 'user' credentials.
Expected that blank registration page is opened

4. Enter username User1, e-mail and password and register the user.
5. Login as User1
6. Open Profile -> Edit Profile

Last name is set to 'User', enter your current password value is also specified.
Expected that last name is empty