I bought a servo system on ebay that uses gecko drives and at first seemed to be a great system... use more than 1 axis at a time and its "twitchy" and sometimes its twitchy with just 1 axis running but the twitchyness is a different motor than the one that should be moving.
This is what I believe is happening. Current is flowing through 1 wire in the cable which of course produces a magnetic field. The magnetic field induces a current in nearby wires (IE causing "twitchyness"). I already asked for a refund on that system as there is nothing I can do about this. Just posting here in the hopes there may be an easy fix before I ship it back.