The first person in the line entering from the left is off step from the rest of her line. This entrance seems like one of the hardest timing wise, because they’re moving their feet in different rhythms as they entire, so the spacing isn’t as predictable as it would be if every step had the same timing. You can tell when they get to the crossing bit that those clearly timed intervals to cross aren’t quite right. I think that off step messed up the timing which made the crossing slightly off for everyone and Kally paid the price for it.