"Use only uppercase" does not actualy convert the session var to uppercase

When the "Use only uppercase" checkbox is checked, and a user tries to submit uppercase text the form does not validate, if they submit lowercase text it will. After looking in the captcha.inc file, i noticed this around line 408 :

  //everytime we create a new code, we write it to session
  $_SESSION['captcha'] = drupal_strtolower($string);

  if(variable_get('textimage_captcha_use_only_upper',0)) {
    $string = drupal_strtoupper($string); 
  }

  return $string;

From what i can tell of this logic, it first sets the $_SESSION var to lower, runs the upper case if that is set, but doesn't change the $_SESSION var to upper. By adding $_SESSION['captcha'] = drupal_strtoupper($string); below $string = drupal_strtoupper($string); it appears to work correctly. Did have one problem where the initial preview of a comment would not validate, but after that it would, i'm guessing it was just a cashed string. Appeared to disappear after unchecking and then rechecking the "Use only uppercase" (Need other people to verify).

  //everytime we create a new code, we write it to session
  $_SESSION['captcha'] = drupal_strtolower($string);

  if(variable_get('textimage_captcha_use_only_upper',0)) {
    $string = drupal_strtoupper($string);
    $_SESSION['captcha'] = drupal_strtoupper($string); //Convert session var to upper!
  }

  return $string;

I think this was supposed to be solved by the setting in the preset that would convert the text input, but that does not appear to affect the input at all, nor could i find a function that handled it, guess that part isn't finished?