If I am viewing my Task list and I click on the the link at the top to add task - the options are prefilled in to the values I have specified in my account settings (New task defaults)
If I then add another task by clicking on the add task link (whilst the task I just added is still in green at the top), I don't have any defaults anymore. If I refresh my task list, then the defaults work again.
Not a big issue, but maybe you can take a look if working on that part of the website.
Looking closer, it only loses the default folder (which I have set to @ To be Processed).
I can replicate the problem -- If I am in "View by Folder" and I have the "All Tasks" tab selected. I click on add a task -- it has my defaults pre-filled in. If I then add another task, it loses the default for the folder.
Also is I click "Add Task" and then select cancel and then click "Add Task" again, my folder default dissapears then too.