Champions vibrating out of Jarvan IV's ult like the Flash

I have noticed this several times while playing matches against bots. Bots will move back and forth repeatedly when Jarvan IV ults them, and they will eventually wiggle out of his ult, defeating the whole purpose of it. It is especially bad if they are close to the edge of it when he ults, as they only need to wiggle a little to get out.

I don't think players can replicate this effect on their own, but the bots have learned, and they do it all the time.