I'd call it a balk.
Here's my thought process:
It would have been more helpful if the umpire had given a reason mentioned in the rule book. Pitchers deceive runners all the time--it's part of the job description.
Similarity to Kershaw is irrelevant. My motto is, "Anything you see pros doing or wearing that looks cool is probably illegal in high school."
Whether it is a balk rests on the umpire's interpretation of "failing to pitch to the batter in a continuous motion immediately after any movement of any part of the body such as he habitually uses in his delivery."
You're banking on the "such as he habitually uses in his delivery" part of the rule.
In general, extra pumps and rotations are associated with the windup motion.
Even if two leg lifts could be considered parts of one continuous motion (and I'll wait for more experienced umpires to weigh in on that question), the momentary pause at the end of the first lift and drop makes it not be one continuous motion. It's more than a change of direction. It's a discernible pause that will inevitably confuse base runners, who are entitled to know when the pitcher comes set, when he starts his motion, and when he is committed to going home.