While calling transaction code F9K3 and displaying the turnovers (payment item) on the tab References, field Payment Order number is empty.
This is the standard behavior.
With old IHC, this field was used to fill the payment order number, now the payment order number has bank area, payment order number, and year. Therefore, the field ‘PT Reference number’ is used instead.
Since this is the system standard behavior, you can use BAdI IHC_BADI_BCA_ITEMS in case you want to have this field updated with specific value.
Best Regards 🙂