We have a small number of reports that a loose and/or arcing laser tube ground termination has caused x/y/z/and u motors to behave abnormally and result in erratic power output.
if the high voltage circuit that energizes the tube suffers from high resistance, poorly terminated connections, interruptions, opens, shorts, etc... the energy can 'leak' out of its designed circuit (wires, connectors, bends, abraded areas, too little air gap, etc...) and arc to other wires, the frame, and elsewhere.
this has been documented to cause erratic and disruptive behaviors such as inconsistent or unresponsive x,y,z, and a axes, garbled, incomplete, and/or shifted output, erratic power output, and other anomalies.
Please check all of the connections in that circuit and make sure everything is secure, fitted correctly, and not arcing anywhere. sometimes the effects are visible. The image below shows a terminal block with a significant amount of thermal insult from a poor connection.
There may or may not be another tube ground terminal in one of the other bays to make swapping the tube easier. Be sure to follow the ground wire from the power supply to the tube as best you can to look for additional connections/terminations.
Here is the hi-voltage circuit (follow the yellow highlighted path):