Access 2016 Subreport with Multiple Columns not Working

I have an Access report that I want to display 16 questions down the side, and the answers for various programs in multiple columns.  I created a report and embedded a subreport (against the same table as the main report) to display the data in multiple columns.  I have the subreport set to 2 columns, the Column Layout to Across then Down, and the subreport section in the main report is more than wide enough to handle the 2 columns of data.

The problem seems to come with the master/child fields.  Since the main report and the subreport have the same source table, I want the master/child relationships to be one-to-one.  In this case, that means two fields: Department and Program.  If I set the relationships this way, my subreport, which displays my desired 2 columns on its own, now only displays one column when viewing the main report in Print Preview mode.  If I change the master/child relationship to many-to many (i.e., on Department only, excluding Program), I then can see my 2 columns of data.  However, since it's a many-to-many relationship, instead of getting data for just the 9 programs, I get those same 9 programs repeated 9 times.

The fact that the many-to-many relationship shows me my multiple columns as desired tells me that the subreport itself is set up correctly, and that I've allowed enough width in the main report to accommodate two columns of data.  What is it about the one-to-one relationship that precludes me from seeing multiple columns?  I'm working on using a different source for the main report, which would make the master/child relationship one-to-many, but am running into the same problem.

Please help!