Solution : https://service.sap.com/sap/support/notes/1603210 (SAP Service marketplace login required)
Key words : 
enabled auto-provisioning failure escape path, auto-provisioning failure escape reason, cup access request workflow, cup access request, role assignment request, terms access control 2010, provisioning partially fails -, attached correction instructions, escape path inconsistently, failed requested roles
Related Notes : 
       
| 1602690 | CUP: Provisioning not working during Escape route | 
| 1591123 | Master Note for SAP Access Control 10.0 - Support Pack 5 |