Hello Aditi,
Very Strange Behavior, I would recommend you to open a CA Support Ticket for further investigation and help to confirm to see the nas tables, if is all there.
Did you try to log with the user: Administrator on UMP and see if you have the same behavior?
If you will be able to see the alert on UMP with the user Administrator, can be an Origin/ACL configuration issue.
Anyway, we would recommend you to apply the latest nas version.
ftp://UIMuser:CnIa24uJ@ftp.ca.com/UIM_Probe_Hotfixes/nas856.zip