If you need to go back and adjust the due date of a task that was previously marked completed you'll need to mark that task and all its successors in progress before you shift the date. If you shifted the date, then marked the task and/or its successors as in progress you'll get a red dependency links on the Gantt chart.
A branch roll up will not force the tasks to update. You'll need to mark all the successors as in progress, go back to the task you were looking to change, move the date back to it's original date, then push it out again. Tasks should update accordingly.