Solution : https://service.sap.com/sap/support/notes/569124 (SAP Service marketplace login required)
Key words : 
read pp master data, read master data, attached correction instructions, terms sequence change, master data, sequence change, production order, planned order, system reads, alternative sequences
Related Notes : 
       
| 454636 | CO40: Routing is exploded repeatedly | 
| 447345 | Reading master data when converting planned order | 
| 391846 | Modif: Reading master data when converting planned order |