Solution : https://service.sap.com/sap/support/notes/1467042 (SAP Service marketplace login required)
Key words :
prerequisites bapi_alm_notif_create isnt designed, partner datawhen calling bapi_alm_notif_data_modify, create / change partners, single step solution, partner function, calling bapi_servnot_save, bapi_alm_notif_data_modify reason, bapi bapi_alm_notif_data_modify, bapi bapi_alm_notif_create, error ix 011
Related Notes :
604300 | FAQ: BAPI_ALM_NOTIF* and BAPI_SERVNOT* |
455832 | Problems with Bapis for servce notificatns functn group IQS6 |