I heard several noises. However on one of the down cycles it sounded like the leadscrew may be rubbing in the clearance hole a the bottom. Take a look to see if it is in the center or rubbing on one side. The motor noises sound pretty normal but in recording it is different than in an open shop with other background noise.
The leadscrew free floats in that black piece at the bottom of the Z. That is more or less aligned by the anti-backlash at the top of the lead screw. Some people have had that come loose and cause problems or it can just wear out.