In the new Reporting Workspace, table widgets are not showing data in UI for subreports, but when you export it displays data as expected. You have created main report and added some subreports as extension reports and confirmed data is displayed properly in the preview mode. After publishing this report and attempting to run from Reporting->Reports you are able to see the data in the main report but most of the time subreports do not show any data.
Clarity 16.4.2
This is no longer reproducible in 16.4.3