I only looked at them to see if there was anything loose. The rack and pinion are definitely worn down. One side of each tooth has an enormous high spot and there is corresponding lowspot on the rack. I didn’t bother measuring it but it was probably about 1mm tall. As far as i can tell, this has been happening for a long time now or else people would have noticed metal dust falling on their parts.
It could have been loose set screws on the pinion for sure.
Personally, I am biased to the idea that the motor mounts are a major culprit. If they flex even a little bit, it shifts the pressure unevenly on the gears which would create weird wear patterns. And once its started i think it may be a positive feedback loop. Wear leads to more wear. If the diameter of the gear is smaller than when it was calibrated, logically it should be the reason for parts being too small in that axis?