The same situation you may see with default theme – Storefront, this means that problem doesn’t relate to our theme. Very likely you face such translation issue because of old woocommerce plugin version, so I would recommend you update xstore to the last version http://xstore.helpscoutdocs.com/article/63-theme-update and update all required plugins https://www.8theme.com/download-plugins/
and then synchronize translation files. Button Sync (Loco Translate plugin http://prntscr.com/glemdq) allows you to synchronize your translation file with updated pot file. It means if we made any changes in template files that may affect transaltion or we added new string for the translation and you updated theme you need to synchronize your translation with updated files. Only after synchronization you’ll be able to translate new strings or strings that were changed.
Also, don’t forget to backup all the files before any update.