Resolved in: 4.7.0
If you are working in a project where the site’s default language is not English and you are also using WooCommerce shipping classes, you will notice that the shipping costs are not calculated for secondary languages.
This happens if you translate the shipping classes after you have saved the shipping method settings. Because of this, these settings aren’t synchronized to the secondary language and prevents correct calculation of shipping costs in that language.
To fix this problem you can re-save the shipping method settings.