I attribute your reference to ping-ponging to Tesla's attempt to give space to larger vehicles in the adjacent lane. A majority of the time it was giving room to semis all the way down to f150 type trucks. Pretty much anything other than a car. So, it was constantly and predictably moving right or left depending on the discernment of the cameras and computer assessing perceived trucks. We all know that the side cameras struggle with identifying the vehicle as a car or truck, so the car would swerve from center to left to center to right based on it's perception. The swerving when no vehicles around in my observation was a false positive detection incorrectly identified by the cameras. The traditional meaning of ping-ponging with auto steering systems is more around the car hunting the center of the lane based on line data only. IMO this is not that.
With that said, I drove on the highway today with the 2020.4.1 update. It did not swerve or make room for larger vehicles. So either they disabled the software or greatly improved it.