3287461 - Stock transfer purchase requisition could not be converted to purchase order due to error

Below error occurs when converting stock transfer purchase requisition to purchase order in app Manage Material Coverage. 
"Stock transport requisition could not be converted.
Doc. type/item cat. NB/U (requisition) <-> NB/ (purch. order)"

SAP S/4HANA Cloud

MRP always creates PR (purchase requisition) of item category (7/U) in case of stock transfers regardless whether it is intra-company or inter-company stock transfer.
Furthermore the system always uses the document type 'NB' as default document types for all kind of PRs (external procurement/subcontracting/stock transfer) created during the MRP planning runs as long as no specific document type is maintained in MRP group. This is the standard behavior of the MRP. 

If it is not allowed to convert these PRs into the desired PO document types, then either the configuration of the purchasing process has to be adjusted.

Go to configuration "Define Document Types for Purchase Orders" to add entries to allow the conversion of PRs with NB/U to POs with NB/blank in purchasing to support this scenario. 

purchase requisition, stock transfer, intra-company, inter-company, monitor material coverage, NB, Stock transport requisition could not be converted, Doc. type/item cat. NB/U (requisition) <-> NB/ (purch. order) , KBA , PP-MRP-PP-2CL , Procurement Proposal (Public Cloud) , Problem