i18n XLIFF dictionary not working

[ichange]

I have dropped in the properly formatted (I ran it through a verifier) XLIFF dictionary file with translations.
i18n is on in settings.yml
I have verified that my culture code is set differently then the default culture, and the same as the culture code in the filename of the messages.(culture).xml
Yet the site just loads in English.
I don't even know how to debug this.
I started putting var_dumps in symfony functions as I walked the path into symfony from the __() helper functions, but nothing.

HELP.

[ichange]

More data.

I have tracked down the cache files and they are in
./cache/frontend/dev/i18n/[32 digit hex code]messages.es.xml/es.cache

If the default_culture is en_US the cache file has an empty JSON string even if the user's culture is set to es (SPANISH)

If we change the default_culture to es (Spanish), and set the user's culture to es the site translates. Once the user with culture set to es hits the site the cache file is populated with a JSON of the entire dictionary file, and the site is suddenly in spanish.