Country of origin population on pick confirm screen from onhand

Summary:

We had created a B2B Sales Order for 2 lines with supply type as 'Buy', Purchase Order, 2 PO's was created out of 2 PR's, COO flowed down from PO line to receiving screen while receiving POs to further Onhand Qty Screen upon receiving. POs were reserved for the sales order, on doing pick wave, when i opened the Pick Confirm screen, for one of the lines COO got auto populated, but for the other line COO didn't populate. We were expecting both lines should show the COO from onhand screen, but it didn't work for the second line, what