What is the correct way to add frontend translation for modules that are installed with composer? The solution should be updated safely. Some extension providers instruct to save the translation file xx_XX.csv into vendor/company/module/i18n/xx_XX.csv but it gets removed when the extension is updated.
It seems that for some reason the translation of some strings does not work when set in the theme's i18n folder. Only when translation is in that vendor folder mentioned before it works.
Or is there some specific reason that would cause the translation not to work from the theme folder and only work from the vendor folder?