The Folder Risk Report is grey out even if you ran few full Discover scans and you receive new incidents.
You have to review the datainsight_operational_0.log. If this file is empty, means the Data Insight Data Refresh service doesn't work.
Restart the Symantec DLP Incident Persister Service and review the log file.
The datainsight_operational_0.log should log the action of the Data Insight Data Refresh service. Wait until the process is finished.
After that, the Folder Risk Report will be populated.