Creating subtasks

I tried to create tasks and subtasks by Asana API, it works, but…
In Asana web interface are subtasks in list of all other tasks (marked red)

How is possible to create tasks by API with this “pattern”? (It was created by web interface)

Subtasks are visible only in detail of parent task. In list of tasks are no subtasks.

My guess is that when you used the API to create the subtask, you specified both a parent task and a project. However, by default, a subtask is not part of any project. So you should have the “normal” result by no attaching the subtask to the project.