Lots of tie rod and drag link ends have a spring in them. Stationary steering movements put quite a bit of strain on the joints.
What you are seeing may be the springs compressing under the load.
I don't know if the joints you have are spring loaded, but it appears they are in the video.
According to the factory service manual the proper way to test the OEM joints is to try to move them up and down by hand. There should be no movement when stressed vertically by hand.
2008 Unlimited Rubicon Automatic