Hello CNC experts, I need your help.

I recently picked up a Gerber Dimension 200 that is working in conjunction with another router that we run (not a Gerber).

I have been having a couple hiccups, where it seems to skip or get held up on the X-axis (photo attached), it still continues to run the job, but is completely off track and I am forced to cancel the job.

Things I have tried:
Removed X,Y,Z Axis screws and thoroughly cleaned and re-greased with White lithium (Manufacturer recommended grease).
Blew out the Black box and checked all connections; capacitors seem to be good, but have not checked diodes with a meter.
Checked all Stepper motor connections and added a small amount of Dielectric grease.
Cleaned the rails; everything moves like butter and doesn't feel like I am hanging up on anything.
Swapped X and Y motors.


I am going to do some more tearing down; but I wanted to check with this knowledgeable group before I waste any more time.

Description of the job is to make cement stamps, where I have to do a rather large cleanout with reversed lettering out of white PVC.

Pictures attached of my hiccup; they happen randomly and in different spots with any type of file sent. Sometimes they will run flawlessly for a while, then another hiccup and I lose the job.

Thanks again for any help

Links to images:
Work piece: https://i.imgur.com/AACY1N8
Step Motors: https://i.imgur.com/sPERAkU
Motherboard: https://imgur.com/9mhkZcz