Variables in variable table interfering with variable translation

Hello,

I had this nightmare of strings all over the place not translating. I tracked it down to this line of code which is supposed to return TRUE (my source language was set to english and the language I was viewing the site with was arabic). But instead it was returning FALSE.

$translate[$langcode] = variable_get('i18n_string_translate_langcode_' . $langcode, i18n_string_source_language() != $langcode);

I searched the database variables table and I indeed found i18n_string_translate_langcode_ar & i18n_string_translate_langcode_en. I have no idea how they were even set, also they were blobs (7 bytes each). I deleted them and everything went back to normal. My question is, how did they get set in the first place? A quick search left me with this line of code:

  $variables['i18n_string_translate_langcode_[language]'] = array(
    'type' => 'multiple_language',
    'title' => t('Enable translation for language'),
    'multiple values' => array('type' => 'boolean'),
    'group' => 'i18n',
  );

But I still don't understand how they were set and where they got their values from. Can someone from the i18n team shed a light on this? Where do these variables get set from? This maybe the cause of half strings not translating bugs and would render the variable translation module quite useless.