pulp-admin tasks list [--all] includes group tasks
When content applicability regeneration tasks are run (or any other tasks belonging to a task group), it is possible to have a lot of tasks running in the system. To avoid flooding the user with too much information when querying for tasks, it was decided to not include the group tasks in that list. The TaskCollectionView already excludes these tasks , but the TaskSearchView does not. The TaskSearchView is the one being used by "pulp-admin tasks list" command.
Recommended fix would be to add search criteria on the pulp-admin side that would tell the search API to exclude tasks where group_id is not None.