When changing the "details" field ("notes" in the API response) or Date/time field ("due" in the API response) of a task in the UI at https://mail.google.com/tasks/canvas does not change the "updated" time of the task and by extension the "updated" time of the tasklist.
Is there a way to change this behaviour to updating the update time no matter what change is made to a task? Could this be a bug? Seems odd to me that changing those fields would not count as an update to the task.
Modyfying a task in any other way results in the update time to be registered as expected. From my experience it appears that only those two fields don't behave as expected