I have a custom workflow set up for a project. When I create a new task, it defaults to the project workflow as expected. When I create a subtask from the Gantt Chart or task details window, it defaults to the same workflow as the task (the custom workflow) also as expected. However, when I am in the table view and I right-click on the original task and click "Add subtask", the new task is given the default workflow. Since this behavior is different from the other methods of creating a task, I believe this to be a bug.
Here is a video of what I am describing. Notice how I add subtasks three different ways, but one does not default to the folder workflow.