This is a product defect (TF00764633).
The Collector operation logs the following warning message:
"[Warning] Cannot find record with: GatheringComputer = [ComputerName], EventLog = ARAdminService, RecordNumber = [REcordNumber], GMT = [TimeValue in GMT]" which leads to empty reports in the report server
Perform the Collector Operation, enable Collector Debug log as per KB: https://support.oneidentity.com/active-roles/kb/45021
Search for a similar 'Warning' message as shown below.
[2018-03-14T00:56:55.140] : [Warning] Cannot find record with: GatheringComputer = DB-ARS721-1, EventLog = ARAdminService, RecordNumber = 6011, GMT = 3/14/2018 3:55:24 AM
If this warning message exist, then after the reports are deployed to the Report server then there will be no data in the 'User attribute management' report.
Due to warning message it is also logged in the Collector database that the assigning of value “0” to Column “EventID” in the table “dbo.EventDescriptions” happens which leads to an empty 'User attribute management' report.
Defect ID 764633 has been resolved in public hotfix (multiple fixes) 250838 which is available for download here.