Solution : https://service.sap.com/sap/support/notes/528009 (SAP Service marketplace login required)
Key words : 
wrong settlement rule, ocm-relevant material, sales order item, terms production order, attached program correction, assembly order reason, process order, assembly processing, program error, planned orders
Related Notes : 
       
| 546181 | Collective conversn: Incorrect dialg box in availablty check | 
| 391846 | Modif: Reading master data when converting planned order |