Solution : https://service.sap.com/sap/support/notes/1530086 (SAP Service marketplace login required)
Key words : 
display proper error message, mitigation assignment workflow reason, symptom mitigation workflow, prerequisites program error, approve & reject button, request type missing, terms access control 10, apply sap note 1528100, apply attached corrections, mitigation assignment
Related Notes : 
       
| 1596296 | Explanation of Mitigation Administrator Roles | 
| 1528100 |