2845383 - Inbound Confirmation 'Material numbers & & do not match up'

Based on SAP Best Practises 'Integration of Procurement with External Suppliers' (scope item 2EJ) You are receiving an inbound Purchase Order confirmation via the SoaP interface 'OrderConfirmationRequest_In'. The postings are failing with error message  'Material numbers 111 111 do not match up' (MMPUR_CONF010)

SAP S/4HANA Cloud All versions

1. Create a Purchase Order with Confirmation Control key triggering an update to the Supplier. 
2. The supplier system sends a shipping notification.
3. The Purchase Order confirmation data is not updated. 
4. Check the App 'Message Dashboard' the inbound XML shows failed with Application error. 'Material numbers 111 111 do not match up'

Incorrect Material data in the payload. The Material Number in the Purchase Order (EKPO-MATNR) is saved on the database with leading zeros 
000000000000000111 (18 characters) but the 'BuyerProductID' in the payload is defined as '111' without leading zeros.

Transfer the 'BuyerProductID' with the leading zeros (18 character field)

2EJ 

MATNR, 2EJ, 2EL, LMMPUR_CONFI03, ME_PO_CONFIRM, EKES, BSTAE, CL_EDI_MM_PO_CONF_PROCESS, II_EDI_ORDER_CONF_REQUEST_IN, CL_EDI_ORDER_CONF_REQUEST_IN, (010)MMPUR_CONF, Material numbers do not match up. , KBA , MM-PUR-GF-CON , Confirmation Control/Shipping Notification , MM-PUR-PO , Purchase Orders , Problem