Solution : https://service.sap.com/sap/support/notes/85236 (SAP Service marketplace login required)
Key words : 
standard task list, additional key words, attached advance corrections, object dependency, longer displayed, transaction cu50, program error, prerequisites
Related Notes : 
       
| 86482 | 3.1I CU50 routing simulation - PRT | 
| 85237 | 3.1I:sales order entry change BOM -> task list | 
| 82179 | 31I Display object dependencies in CU50 | 
| 73610 | 3.1H: CU50 'Multi-level task list configuration' | 
| 73584 | 3.1H CU50: Object change BOM <-> Standard task list |