add_filter( 'wdp_save_cart_item_keys', function ( $keys ) {
	$keys[] = 'bundled_by';
	$keys[] = 'stamp';
	$keys[] = 'bundled_items';
	return $keys;
} );

add_filter( 'wdp_skip_cart_item', function($skip, $item, $product) {
	if( isset($item['bundled_by']) ) //ignore product inside bundle
		$skip = true;
	return $skip;
},10,3);

add_filter('wdp_cart_item_data_before_apply', function($cart_item_data, $original_cart_item_data ){
	$cart_item_data = array_merge($cart_item_data, $original_cart_item_data);
	return $cart_item_data;
},10,2);

add_filter('wdp_original_cart_item_data', function($original_cart_item_data){
	return array();
},10,1);