during the test your wiring step of setup, 2 out of 5 times the up arrow moves the head up. The other 3 are down. The next 5 times might result in 1 out of 5 or 4 out of 5. What is this?
Sounds like your wiring is not hooked up right or some of the wiring might be touching another terminal intermittently.
Turned out to be a cold solder joint on the z-axis of g-shield
I had a NO solder joint on pins 1-7 of my first gshield! But customer service had me fixed up with a replacement the next day 
A bit of a quality control issue from the vendor I suspect.