3591319 - Partner function display in S4HANA public cloud procurement APPs

The 'Display Purchase Order - Advanced (ME23n) webgui tile displays the partner functions with a different partner function code from the ones displayed in
the fiori APP 'Manage Purchase Orders' or the ones returned via the V4 Odata API 'api_purchaseorder_2'. 

SAP S/4Hana Cloud - Public Edition 

1. Call a purchase order via the 'Display Purchase Order - Advanced (ME23n) webgui tile and display the partners in the Header Partner TAB. 
2. Call the same purchase order via the 'Manage Purchase Orders' APP.
3. Execute a GET request using the V4 Odata API  'api_purchaseorder_2'.  
   EG: */sap/opu/odata4/sap/api_purchaseorder_2/srvd_a2x/sap/purchaseorder/0001/PurchaseOrder(PurchaseOrder='4500000000')?$expand=_PurchaseOrderPartner
4. The Vendor partner function shows 'VN' in ME23n but in the fiori APP and API it shows as 'LF' 

Standard system behaviour. 
Partner functions are shared across different applications and can be language dependent in some cases. 
In the context of OData services, it is not possible to use a language-dependent field as key field. For this technical reason the 
fiori APP and Odata API are designed to use the internal partner functions which is described further in the respective SAP Help documentation. 

For purchase orders the following partner functions are relevant: 

CP    Contact Person         =  internal partner function AP 
OA    Ordering Address     =  internal partner function BA 
CS    Copy Supplier          =  internal partner function CS 
FS    Freight supplier        =  internal partner function FS 
VN    Supplier                  =  internal partner function LF 
PI    Invoicing Party         =  internal partner function RS 
GS    Goods Supplier        =  internal partner function WL 

V4 API documentation 
Manage purchase Orders documentation 

Partners, EKPA, TPAER, TPAUM, F0842A, C_PURCHASEORDERPARTNERTP, MM_MAINTAIN_PARTNERS  , KBA , MM-FIO-PUR-PO-2CL , Fiori UI for Purchase Orders (Public Cloud) , MM-PUR-PO-2CL , Purchase Orders (Public Cloud) , Problem