Make sure that XStore theme and XStore core plugin translation files placed into wp-content/languages/themes and wp-content/languages/plugins folders, not into wp-content/themes/xstore/languages folder.
After every update, you need to synchronize translation – https://xstore.helpscoutdocs.com/article/103-translation-files-update Sometimes new strings are added, and only after synchronization, you’ll be able to translate new strings or strings that were changed. Not always, but some strings can be missing after the sync and you need to find and translate them one more time, this is independent of us and relates to WP functionality. Also, do a backup of all the files before any update – https://xstore.helpscoutdocs.com/article/63-theme-update
