How to show next-gen project Issues in Boards

[Joseph W_]

If I create a filter that shows issues from all of our next-gen projects,
JQL: project in (project1, project2, project3)

and then use this filter (available to all in org.) for a Board or Dashboard,
the result is NO issues showing on the Board or Dashboards.

When I add classic projects to the filter, issues load onto both the Board and Dashboard just fine.  So why are next-gen project issues not loading?