Solution : https://service.sap.com/sap/support/notes/666790 (SAP Service marketplace login required)
Key words : 
system generates runtime error message_type_x, attached source code corrections, user-defined program, program error, error text, bapis bapi_alm_order_get_detail, nested perform, terms nested_perform_on_commit, swe_event reason, update task
Related Notes : 
       
| 736288 | Notes for downgrade kit ALMBAPI III | 
| 708508 | Downgrade BAPI_ALM_ORDER_MAINTAIN -> errors |