Solution : https://service.sap.com/sap/support/notes/592523 (SAP Service marketplace login required)
Key words : 
symptom transaction /sapapo/bop_result, changed order items, backorder processing run, parameter process tab, requested delivery date, confirmed schedule line, request schedule line, source code corrections, /sapapo/bop_update, postprocessing' mode
Related Notes : 
       
| 603874 | Material staging date updated incorrectly |