3763593 - Purchase Order description includes 'non-catalog-item' from supplierpartid

When I send a Purchase Order (PO) from SAP ERP to my SAP Business Network the value 'non-catalog-item' is being included into the outbound payload, and there is no mapping setting it to do so.

SAP Integration Suite, managed gateway for spend management and SAP Business Network

defaultSupplierPartID, SupplierPartID, Non-Catalog-Item, purchase order description, cXML ItemID, cross-reference, mapping, Integration Suite Managed Gateway, CIG, Business Network, PO mapping, short text, s/4hana short text, ariba purchase order, description field , KBA , BNS-ARI-CI-AN-PO , Managed Gateway for Business Network - Order , Problem