Toolset - WPML

Problem:
I'm trying to translate a field group from a post type. To do that, I went to WPML > settings > Multilingual Content Setup > Post Types then I selected "Translatable —use translation if available or fallback to default language" option for the post type that the field group is assigned to. The custom field's group doesn't appear for translation for most of the posts.
Solution:
When the fields are missing from the translation page, just simply edit the original post, hit the Update button, and try again to do the translation.