Fixed two-factor sign-in returning to the login page.
- The code form sends itself when the sixth digit is entered. Pressing Enter or Verify while the code was being checked sent it a second time, and the second send went to the login page without signing in. The form is now sent once.
- If a code arrives with no sign-in waiting for it, the login page says that the sign-in did not finish.
- The code fields in Account settings, for turning on two-factor authentication and for changing the email address, are also sent once.