BOM type MTO related problems

Assume a product with bom type MTO has entered in a Sales order

• sales order entered and ‘completed’ then SO has triggered a MO. (SO qty =5)
•We ‘completed’ the MO (MO qty=5)
•We started reporting MO partially –> received 2 (receipts & issue)
•Then we ‘close’/’void’ the SO (assume customer cancelled the order, so we need to void or close the SO)
•We found that MO qty becomes ZERO, delivered Qty=2 in the MO header. ‘Balance required Qty’ for the components are still reflecting in MO components lines and hence appear in MRP
•MO is still showing in ‘completed’ status
•We can still do further reporting (receipts & issue) for the above MO (though MO qty is ZERO)
•Now if we try to ‘close’ the MO, we get attached error msg