Solution : https://service.sap.com/sap/support/notes/921184 (SAP Service marketplace login required)
Key words :
incorrectly set check boxes, symptom tables t77evoptt, terms sapfh5ah reason, field spras, field sprsl, unicode change, text flags, language code, table refers, text fields
Related Notes :
| 672835 | Textflags could cause problems during Unicode conversion |