Please I need this fixed. The discount plugin developers have written:
Our dev team had a check and here are the details :
* By default the key start with _ will be the hidden meta value.
* But, in the PDF invoices it is loading.
* We also tried to remove the field through the woocommerce events woocommerce_order_item_get_formatted_meta_data
woocommerce_order_items_meta_get_formatted
* But, we are unable to remove from our end.
We recommend you to check with the WooCommerce PDF Invoice Builder Pro developer if they have any hook to remove/hide any order meta values in PDF.