Solution : https://service.sap.com/sap/support/notes/120803 (SAP Service marketplace login required)
Key words : 
relevant procedure/action, unauthorized model change, additional key words, attached advance corrections, symptom values, object dependencies, author 'user', input exists, input status, master data
Related Notes : 
       
| 134247 | Classification nodes and author information | 
| 126932 | Incorrect author information / lost values | 
| 126623 | Interval values in characteristic value assignment | 
| 117612 | Values from procedure/action cannot be deleted | 
| 111978 | Rel. 4.5A: Incorrect author info for constraints | 
| 110271 | 4.5A:Missing char. on char. value assignment screen | 
| 97285 | 3.1I configuration: inconsistencies due to ... |