Solution : https://service.sap.com/sap/support/notes/779872 (SAP Service marketplace login required)
Key words : 
terms afvgd-ltxa1 reason, attached correction instructions, bapi bapi_alm_order_maintain, short text, program error, solution implement, program corrections, 40 characters, transferred, prerequisites
Related Notes : 
       
| 780775 | BAPI: Problems in text processing | 
| 780743 | BAPI: Operation short text is not transferred | 
| 778602 | BAPI: 1. line long text not transferred completely | 
| 771445 | BAPI: Incorrect long text processing | 
| 708508 | Downgrade BAPI_ALM_ORDER_MAINTAIN -> errors |