user_save() regenerates session without password change

Log in from two different browsers, edit and save your account in one (don't change the password), and you become logged out in the other.

In user_save() there is this code:

    // If the password changed, delete all open sessions and recreate
    // the current one.
    if (isset($array['pass'])) {
      sess_destroy_uid($account->uid);
      sess_regenerate();
    }

However, when the user edit form is submitted, $array['pass'] is set (but empty), so the session is regenerated, even though the password doesn't change.