imagecache_external_generate_path() returns different outputs

It seems to me that imagecache_external_generate_path() either returns a filepath string, or returns a FieldItemList object depending on if the image was called externally or if we have the image already. I think the following code:

    if ($needs_refresh === FALSE) {
      return $filepath;
    }
    elseif ($filepath = imagecache_external_fetch($url, $directory . '/' . $filename)) {
      return $filepath;
    }

should be...

    if ($needs_refresh === FALSE) {
      return $filepath;
    }
    elseif ($filepath = imagecache_external_fetch($url, $directory . '/' . $filename)) {
      return $filepath->getString();
    }

Can you please confirm? I think your module handles it later on, but Im calling this function directly in some custom code and the return is inconsistent.