The split jerk is essentially a two-phase with the back foot landing initially and hence getting traction initially. This has the impact of pushing the bar forward under the bar as it locks out overhead.
This exercise teaches the correct “prancing” motion of the front foot although reinforcing the generate from the shoulders in front of the neck. If this is a issue of yours or one of your athletes, contain the movement early in the session right until the footwork will become well ingrained.
As additional proficiency is attained, the exercise can be little by little moved even further back in the training right until it can be eliminated completely.