New set of problems

Sorry but i can not figure out anything from that video, can you do one while moving under power?
And are those stepper or servo motors?
I have to ask as ClearPath servos were not servos at all a few years back, just steppers, some with encoders.

These are servo motors
ClearPath Integrated Servo MotorCPM-SDSK-2321S-RLN2$610.00 
ClearPath Integrated Servo MotorCPM-SDSK-3441P-RLN1$432.00 
The one that is giving me a problem cannot hold a constant speed and this causes a problem with the THC due to changing speed see in this  video of a straight line cut.  It makes the torch bounce up and down due to speed changes.
drive.google.com/file/d/1B-0kLopIEspzgQS.../view?usp=drive_link
If I change the direction to the other axis it cuts fine no bouncing up and down.

To explain what I was trying to say is a stepper motor and these servos will generate voltage when moved without power. With no power on if you move an axis it will make enough of a signal to for a very short time try to stop your motion, then release it to move again. This is similar to rolling down hill in car and taping the brakes from time to time. In the first part of the video it shows that action and the second part that does not happen.
Try this on your table with the X or Y axis without power, moving at a moderate speed. You will feel this stopping action for an instant then release.

Not servos, just have a look at the torque graph, steppers. At least they seem pretty good quality.
That does not help you at all, except maybe buying the cheapest drive/motor you can find and replace the misbehaving one. Might only need to change the scale as i would assume the existing ones use high microstepping.
Do those have encoders? That is the only thing that might cause such behavior, namely, the encoder has a rusted slot wheel, and if so that would be worth trying to fix.

They are BLDC motors with an integrated servo amplifier. They close the loop between the drive and motor but they do not output the encoder signals. There is an option to get a pretty crude pwm output that is linear with the speed, but I would not use it for feedback that has to be precise.
Yes I have used them and no I don’t like them that much.

Did you see the torque curve?
Those are not servos by any stretch of imagination.
So no, they are not BLDC servos, although steppers can also be seen as BLDC motors, just 2 phase.
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Torque curve shows steep drop of torque as the speed rises, indicative of stepper motors, max speed is 1700RPM at 75V, not usable at all above a certain point (forgot, on the phone), and does 700 or 800 max RPM at 24V, again not usable above probably 300RPM as the torque drops considerably.
The drives probably use high microstepping to lessen vibration, so what is the step rate per rotation on them?
I really hope they do not use pulse multipliers....
Edit:
Forgot to add, servo motors of similar size spin easily at 4000 to 5000RPM without much loss in torque.