Solution : https://service.sap.com/sap/support/notes/871851 (SAP Service marketplace login required)
Key words :
subsequent field symbol access, runtime error getwa_not_assigned occurs, invalidated loop reference, pl 84patch number, loop field symbol, reset field symbol, runtime error getwa_not_assigned, current loop line, single delete record, delete adjacent duplicates
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 |