Are you using local JSON (acf-json folder in the theme)? It could be that the fields in question exist in the JSON file and this is the reason they appear when editing a page and not when editing the group. ACF will always pull from the database when editing a group and will always use the JSON file (if it exists) when editing something with the fields. If you using local JSON try updating the field group on the old site and syncing it on the new site.
Welcome to the Advanced Custom Fields community forum.
Browse through ideas, snippets of code, questions and answers between fellow ACF users