“... so that you can easily use Content Moderation on one (or some) of your migrated content types”. This would have been the longer version of this post's headline (if it hadn't been for the SEO restrictions regarding headlines' length). And it's precisely then, once you try to turn on content moderation on some of your your site's content types, that you realize that... ups... Drupal 8 exports content with a wrong langcode legacy! You have problems, I have solutions! Here's the “embarrassingly” simple way to fix your invalid translation(s) so that you can go ahead and enjoy Content Moderation's functionality on your Drupal 8 site: