Recreating backordered scenario on back to back sales order

Summary:

Hi, I am trying to create a backordered line scenario in the back to back sales order.

As a part of it, I have taken 21 quantity in sales order for which a work order has been generated for 21 quantity of which I have partially completed 11 and 10 not completed. On the shipment side I have pick released, so the shipment lines splitted into 11 quantity- released to warehouse and 10 quantity as backordered. Closed the work order without completing the remaining quantity.

But in the sales order still in the Awaiting shipping. Does'nt the sales order line also split the line at this and make the remaining quantity as back ordered?