Solution : https://service.sap.com/sap/support/notes/215088 (SAP Service marketplace login required)
Key words : 
additional key words sis, partner-related statistical data, incorrect program behavior, program correction contained, changed item partner, data related, partner data, partner change, item level, item partners
Related Notes : 
       
| 204130 | SIS update: Collective note | 
| 174289 | SIS: Partner structure not filled |