FedEx Return only International non-document shipment does not print ref field

FedEx International Return Only shipment with commodity (non-document), does not print Reference Field (contains cost center code) is not printing on label. We need to confirm the information is being sent to FedEx so it will be used in billing.
Documents only version of the same shipment does print the reference field. See attached examples, CI for FedEx International Return Only shipment with commodity (non-document) included for reference.