When you click “Tasks” tab, a task list of tasks in “any projects” is shown, but actually it shows only TEDTalks.
If you select “any projects” explicitly, it shows tasks of all projects including TEDxTalks and TED-Ed.
The same thing happens on Assignments. If you click “Assignments” link of someone in the Members tab, the menu of the list indicate that it is a task list of “any projects,” but actually it shows only TEDTalks.
This issue is resolved by making “TEDTalks” the default of “tasks in” menu.
This is a known issue – the TED team has a lot of special logic in place to show certain tasks. We'll be moving to a new collaboration system and will address this when we move over.