Solution : https://service.sap.com/sap/support/notes/780743 (SAP Service marketplace login required)
Key words : 
typeiv_afvgd_up_ktsch   type          afvgd_ibapi_update-ktschnow implement, terms operation long text, operation short text, standard text key, function module ibapi_o_text_check, attached correction instructions, changed correctly, bapi_alm_order_maintain reason, updated correctly, solution extend
Related Notes : 
       
| 897391 | BAPI: Item text not adjusted in operation PReq II | 
| 860249 | Component long text is not updated in PReq | 
| 780775 | BAPI: Problems in text processing | 
| 779872 | BAPI: Problems in long text processing for operation | 
| 772580 | BAPI: Changing short text does not change long text | 
| 708508 | Downgrade BAPI_ALM_ORDER_MAINTAIN -> errors |