3257400 - Some document type are not available in the Manage Purchase Orders app - SAP S/4HANA

Document types (e.g. custom types) are maintained in customizing: SPRO -> Materials Management -> Purchasing -> Purchase Order -> Define Document Types.
When creating a PO in the Manage Purchase Orders app (F0842A), some maintained document types cannot be selected in the "Purchasing Doc Type" dropdown.

In addition, they are not displayed in the Purchasing Doc. Type filter (even though there are POs shown in the result list). 

"Image/data in this KBA is from SAP internal systems, sample data, or demo systems. Any resemblance to real data is purely coincidental."

• Materials Management (MM)
• SAP Fiori
• SAP S/4HANA 2020
• SAP S/4HANA 2021
• SAP S/4HANA 2022
• SAP S/4HANA 2023

F0842A, GET_PO_TYPES_COMPATIBLE_TO_NB, IS_PO_TYPE_SUPPTD_IN_MANAGE_PO, ls_t161_nb, t161, rt_po_types, custom, document, type. Purchasing Doc Type, filter, framework, FO, dropdwon, drop, down, drop-down , KBA , MM-FIO-PUR-PO , Fiori UI for Purchase Orders , Problem