https://userapps.support.sap.com/sap/support/knowledge/en/2825530
2825530 - Invoice and PO History: Item Reference is not filled for services - SAP ERP & SAP S/4HANA...
An invoice with reference to a Service-PO is posted via MIRO. After the post, in the tables EKBE and RSEG, the field Item of a Reference Document (LFPOS) is...