Solution : https://service.sap.com/sap/support/notes/778602 (SAP Service marketplace login required)
Key words : 
terms caufvd-ktext reason, attached correction instructions, symptom appart, short text, bapi bapi_alm_order_maintain, program error, solution implement, program corrections, 40 characters, transferred
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 | 
| 771445 | BAPI: Incorrect long text processing | 
| 708508 | Downgrade BAPI_ALM_ORDER_MAINTAIN -> errors |