I had similar issue with Polish translation and ended up deleting good chunk of it. I'd swear I translated a lot of entries that I've found in english version. For my purpose I wrote simple script for detecting english version translations: https://github.com/Srokap/polish_translation/blob/master/validate.php

I suspect smb pulled translations in `developer` mode (default) instead of `translator` and pushed english translations to upstream by mistake. I pulled polish translations into git repo to avoid/detect it in future. Might consider setting up git repo with all languages updated ie. daily purely for the purpose of monitoring changes happening on transifex.