yes, i did try in neutral.
i found a thread on here where someone appeared to have almost the exact same issue as i experienced, and had discovered that one of the little fingers inside the xyz was bent and so presumably not touching its track.
i opened the original (black) xyz last night and found exactly the same problem -- one finger was slightly bent. i have realigned everything and reassembled that one as a spare, but for now i will stick with the xyz from the parts truck (beige) since it seems to be working.