Afraid to use my "Z"...not sure if stepper or driver is acting up...

Been using my BP Series 1 more in the last few days than I have in
the last few years of owning it...last night while doing some spot
drilling, the Z axis failed to move even though the turbocnc screen
said "in motion"

no noise at all from the Sigma stepper motor, upon doing an e-stop,
I checked all the wiring and it was fine. I went into "jog" mode and
motor wouldn't turn at first and then I did another command and it
worked.

did a few dry test programs and the Z would not move about 1/2 the
time it should have (up or down)

today I jogged the Z with no issues at all for about 5 minutes in
different increments...worked flawless...

What should I be testing??

Gecko 201's...

Thanks,

Mike