CDN not working on multilingual site
Found the issue the Language Selection Page module is causing the issue https://drupal.org/node/2283985. You can see the styles exemption in the code. For you I would add in the advagg and cdn paths to the language_selection_page_blacklisted_paths variable. You should find it under "Paths blacklist" on the admin/config/regional/language/configure/selection_page page.

Gotta run will add in the exact paths tomorrow, but it will be something like 


  farfuture/*
  sites/default/files/advagg_css/*
  sites/default/files/advagg_js/*
  httprl_async_function_callback