It is possible to create Purchase Requisitions against Sales order which have not been approved and have the status In approval. It is also possible to convert these requisitions to Purchase orders.
SAP S4 HANA Cloud 2011
This is the standard behavior. A Sales Order generates a Purchase Requisition and a Purchase Requisition will be converted to a Purchase Order. Each successor document checks basically the status of the predecessor document. So the Purchase order will not check against the Sales order, but against the Purchase requisition. When creating the Purchase requisition however, there is no check against the Sales order.
The creation of Purchase orders can be customized by using the Final check BAdI for PO. This way the status of the Sales order can be checked, and the creation of the PO prevented.
Purchase Order, Purchase Requisition, Sales Order, Third-party , KBA , MM-PUR-GF-TP , Third Party Order Processing , Problem