10.4.1 The pitcher must take only one step/stride forward toward home plate as she delivers the pitch.
This is from the 2014-2015 NCAA book, which is the only one I have access to at the moment, but the rule hasn't changed.
Since it appears in the video that her pivot foot loses contact with the pitcher's plate, that is a step forward, not a sliding of the pivot foot on the pitcher's plate.
Very unlikely that this would be called in real time. It would probably be very difficult to determine whether or not the foot left the ground as opposed to sliding forward on the pitcher's plate.