still don’t know what exactly fixed it. but now it’s all right.
i have also found another way to show custom fields:
if you want to show a specific field in a specific place, in the CartListDisplayer.php, add to the function lcp_build_post anywhere you like:
$lcp_display_output .= get_post_meta($single->ID, ‘featured’, true);
where featured is the name of yuor custom field.
Hope it can help someone.