Hi Sumit,
I have checked your issue. This is a known issue in GRC while assigning FFID to users the users will not come sometimes due to few reasons as mentioned below:
i) Path:-
SPRO -> GRC -> Access Control -> Maintain Configuration settings
Check Configuration Parameter 4010, you will get to know which FFID role has been maintained under GRC SPRO settings.
If there is no role maintained here means you need to maintained the required FFID role.
ii) Now, check every FFID must be assigned to the FFID role which is maintained in the Configuration Parameter 4010.
iii) Fire-fighter should have the basis access to use FFID as well.
Also, run the sync.jobs auth sync and repository object sync then check user will come while assigning to FFID.
Regards,
Biswajeet