New Admin Monitoring Workspace - why are workspaces in activity not displayed?

I am a global admin in our tenant.  I've enabled the Admin monitoring for tenant admins.  I see the new Admin monitoring workspace and see the Feature Usage and Adoption report and dataset, as well as the Purview Hub report and data set.  If I go to the Activity details tab in the Feature Usage and Adoption report, there's a column for Workspace name, but it just says "NA."   I'd like to know what workspaces are being used.  Is there a way to get this info?  I'm not sure what value the report is without knowing what is actually being used.