I hope to ask a question about composite report building.
Context: I am building a composite report showing the number of leavers and active headcount by Country. So far, I have a matrix report as sub-report, showing the number of leavers of a certain month, grouped by Country field. I am using All Active and Terminated Worker Data Source (BO is Worker) for that sub-report.
Issue: When I add that sub-report into my composite report column, I always receive this Page Error message: "Encountered unexpected error joiningBusinessObject cannot be null while building Market on your report. Please fix it and try again." I have made sure that my control field has BO as Worker, Display Field Override as Country and there is no blank field in my sub-report. I don't know what else to do to fix this issue.
Hope you can give me some advice and thank you so much in advance!