Solution : https://service.sap.com/sap/support/notes/871851 (SAP Service marketplace login required)
Key words :
GETWA_NOT_ASSIGNED, loop field symbol, DELETE
Related Notes :
| 872720 | GETWA_NOT_ASSIGNED or SYSTEM_DATA_ALREADY_FREE in the LOOP |
| 866639 | Core dump when unsharing a HASHED TABLE in a LOOP |
| 19466 | Downloading SAP kernel patches |