The outline and complete user reports (shown under reports on the users profile page) will not show activities that have a "view" capability to the parent role.

Example - The attendance activity defines the "mod/attendance:view" capability and the modinfo built for the parent role sets uservisible using is_user_access_restricted_by_capability() for each module before allowing it to be displayed - which means that the parent user must be enrolled in the course to allow the outline/complete report to show for that course/user.
The Forum activity does not have a mod/forum:view capability so this activity will show to users with a parent role.

I wonder if we could write a hook to the user complete/outline reports that allowed a module to override the uservisible flag and allow the module to check if the user can access the module instead?
https://github.com/moodle/moodle/blob/master/report/outline/user.php#L126

I'm not sure how that hook should look - I'm happy to do the development on this if someone has any great ideas!