Please find the complete steps with issue details.

1. Link Bank Document type in the PO.

1. Manage letter of credit

1. Link the LC and Generate Shipment

Creation of letter of credit Agreement

1. Generate shipment numbers by clicking on “Purchase Order shipment”

1. Confirmation of Shipment

1. Shipment number selection in the product receipt

1. Shipment selection in Invoice

If The PO bank document is LC, then Shipment number is mandatory in both Product receipt and vendor invoice. However, this validation is not working if The vendor invoice is posted automatically through workflow -Automated TASK.

Below shipment vouchers are affected, Missed to select in invoice.