This is normal for radial tires. I have seen this on my own tires. If you rotate tires as I do, front to back same side and back to front opposite sides, the tires that had their rotation direction reversed which will be the rear to front opposite side tires will eventually have the chopping as you call it, reversed. I’d say don’t worry about it.
PS: In reality, it is easier to feel rather than see this. Use a couple of fingers to rub the top of a tire front to back and then back to front. If you don’t feel a difference, the tire may have been recently rotated and is in the middle of transition from one chop direction to the other. Thanks for the word, now I know what to call it.