Mine occasionally will run into one of the sides and bounce off of it (stutter). Video:
What it looks like to me (I haven't cracked the code) is that the two switches are carefully correographed to get 3 position states (left, right, center). And there seems to be very little margin between far left, and far right, and the plastic guide running into the ball release from the opposite arm, causing step loss (the stutter). I am guessing I will need to go back in there (after waiting on Barry to confirm) and adjust one of the switches / it sets too late.
To remove the plastic guide, there's a set screw (2.5mm). This photo is the angle for which the set screw hole is accessible.
This is what the switches look like (4x 7mm nuts holding mech on)
This is the TWO cam plates attached to mech. Apparently on the prototypes / engineering samples there was just one.
This is a video of cam action and switches. Since I have no idea what "good" looks like I just sent this to Barry and will wait and see
And here it is reassembled. It worked better for a few games then it came back.