Solution: Exclude WooCommerce Product custom post type

Just wanted to share how to exclude WooCommerce Products from getting the default featured image.

function dfi_posttype_product ( $dfi_id, $post_id ) {
  $post = get_post($post_id);
  if ( 'product' === $post->post_type ) {
    return null; // the original featured image id
  }
	return $dfi_id; // the image id
}
add_filter( 'dfi_thumbnail_id', 'dfi_posttype_product', 10, 2 );

Hope that helps anyone looking for help with how to exclude one custom post type.

https://wordpress.org/plugins/default-featured-image/