Would that be like post dating a check?
I had to watch the video, but no, he “pre-dated” it, to August instead of September. Innocent error to make around the turn of the month.
Contrary to conventional wisdom, post-dating a check is a meaningless exercise. There are four items necessary to the execution of the instrument, and the date is not one of them; it bears no more significance to a bank than the “memo,” which is entirely for the benefit of the signer.