If a preplant/preemergence HPPD containing product has been applied, do not apply a solo
application of CAPRENO Herbicide in the same season; always include an additional effective
mode of action herbicide(s) as a tank mix partner.

To me this reads as a guideline for stopping the development of resistant weeds and has nothing to do with the safety of the corn crop. And that you need to add another mode of action for controlling weeds in your post spray.