For those unable to see video, robot finishes tip dress, backs away, starts to do its first gun squeeze. As the upper gun arm starts to close, at about 1.5 inches away from the lower gun arms, the upper arm goes into, what looks like, free fall, bouncing on the bottom gun arm six to seven times, gradually working its way closed. Looks a lot like a bouncing ball.
When finally closed, it continues on with the rest of the tip measuring routine.
Doesn't happen all the time and happens rarely.
Hope this helps.