I mentioned this a little in my write-up. Too me the QB was running away and Jennings was chasing him. Jennings dove for the QB and as the QB was moving away . The QB jumped to make the throw. This combination of these actions would cause a tackle to be a little lower. Too me it is a hustle play where you have to take in consideration of all the players. I hope this answers your question.
How can the rule be changed to account for such an event?
Not that it will be changed.