Solution : https://service.sap.com/sap/support/notes/388479 (SAP Service marketplace login required)
Key words : 
global control flag, -party order processing, material requirements planning, source list entry, system behavior back, outline agreement exists, planned orders generated, scheduling agreement item, subcontracting mrp areas, separate subcontracting segments
Related Notes : 
       
| 743312 | Implementation of BAdI MD_SUBCONT_LOGIC | 
| 550219 | FAQ: Subcontracting in the material requirements planning | 
| 214298 | MRP: 3rd-party order processing for subcontracting I |