The problem is that ACF saves values on the “save_post” hook and in\f you look at where this is done, line 3581 of /wp-includes/post.php, you’ll see that the action “save_post_{$post->post_type}” happens before “save_post”.
You need to use either “acf/save_post” or “save_post” with a priority > 10
If you want to use this hook then you’d need to look in $_POST[‘acf’] to get the values.
