That’s unsurprising, because simple patterns don’t have the exact motions required to knock the motors / hardware awry. Right now, the cat’s interior is the definitive testcase: it always fails, which means you’ll know when you find the problem. 
That’s important new news: the problem affects both axes.
The stepper drivers have two LEDs to the right of the terminal block from the controller:
- Green = power
- Red = alarm
In normal operation the green LED should be steady and the red LED should be off. Is that what you see while running the cat interior?
The stepper driver data plate shows the power supply range is 24 to 50 VDC. The Ruida 6442 data plate shows the usual 24 VDC power input and the manual says “compatible with 36V for power supply, but not recommended”.
I’d lay big money saying the machine has a single 24 VDC power supply for both the steppers and the Ruida controller. That would be at the lower limit for the steppers (which are having problems) and at the upper limit for the controller (which would develop heartburn).
Having eliminated all the other problems, I put further money saying the power supply is failing. They’re typically under-sized for the machine’s total current and seem to fail early.
I’d expect the voltage to be about 24 VDC while the machine is idling and a bit lower when it’s running. Without an oscilloscope it’ll be almost impossible to catch a glitch in action, but the LEDs on the stepper drivers may flicker to indicate a brownout.
At this point I suggest preemptively replacing the power supply with one rated for 15 A or so:
- Steppers draw 6.6 A (both set for 2×3.31 A)
- Another 2 A for the controller (there is no spec)
- A few amps for lights & other gadgetry
That adds up to 10 A. A 50% margIn seems prudent given that the stepper drivers are at the low end of their range.
Side bet: The OEM power supply will be rated for maybe 5 A, definitely less than 10 A.
Protip: Get the power supply from a reputable seller who does not also offer skimpy beach attire, pet food bowls, and acupuncture needles …