Solution : https://service.sap.com/sap/support/notes/515328 (SAP Service marketplace login required)
Key words : 
newly generated subitem, backorder process, oltp system, terms transactions, /sapapo/bop, /sapapo/bop_updateregelneuauswertung, update reason, backorder processes, solution implement, maintained
Related Notes : 
       
| 375193 | Backorder processing: Composite SAP note on posting |