Issue in Back to back Sales order

Summary:

In a back to back sales order, we had a scenario where for a line the work order was generated but automatically it has unassigned the work order and automatically put the status as cancelled and got the reservation to onhand. But the work order is not cancelled. But in Supply Chain Orchestration for the work order document the line is shown as cancelled. If it has to reserved to onhand , then why did it generate the work order and then unassigned it.

When the supply line status is cancelled in sales order but the work order is not cancelled. why.