Subtasks do not inherit version information from parent task

When creating a new subtask, intuitively one would expect that, if the parent tasks is attached to a particular version (affects or fix), then the subtask would inherit that version information. This does not occur, and instead we find that we have to specifically set the version information in a subtask. I cannot think of any occasion that a subtask would be affected to a version other than that of the parent task.