Figured out what the problem is and it's not really a bug.
Most of my tasks with sub-tasks are projects. Because I use the main task as sort of a "container", it doesn't have a due date since I haven't figured out how to make that work for me. The main tasks don't show up on my hotlist because they don't meet the criteria so there is nothing to show a sub-task for even though the sub-tasks are on the hotlist.