Best posts made by Wally

@chrishamm - finally figured this out. I was using 5V from the 6HC mainboard to power my display. During power off with M81, the 5V line voltage to the display would vary a lot (enough to cause the problems seen). Connecting the display to a separate (dedicated) 5V power source has eliminated the problem reliably. Probably should have used an O-Scope to quantify the variation; however, the cleaner power clears up the display.

Here is a photo of what I'm using.

• Raspberry Pi 7" Touch Screen Display
  https://www.amazon.com/Raspberry-Pi-7-Touchscreen-Display/dp/B0153R2A9I
• Smart Pi case (to hold) https://smarticase.com/
• A 24" ribbon to reach my Pi (not able to mount in the Smart Pi case as the ribbon cable to the Duet 3 board isn't long enough
  https://www.amazon.com/gp/product/B00M4DAQH8
• Touch screen works, but I rather use the wireless mouse seen in the photo (I also have a wireless keyboard for when I need to key in G or M Codes)
  7" isn't too bad if you have a good mounting plan and cable plan
  

Once you have your steps/mm feed rate working, you will want to know what your hot end is capable extruding by volume. Need to know so your X-Y moves/speeds set in your slicer program are not so fast that the hot end cannot extrude filament to match. CNC Kitchen has a good article w/ video here:
https://www.cnckitchen.com/blog/flow-rate-benchmarking-of-a-hotend

@oozeBot - thanks for the picture - literally worth a 1000 words....
PS: I have a very similar setup too!

Have you tried using a Cricut cutting mat ?
My wife uses a Cricut and the mats last a long time and have a low tack adhesive to hold your cutting material (paper, vinyl, gasket material) while the knife passes around the path.

@BryanH Thanks for the details. Suggest changing your main board jumpers and power the Pi independently (separate power source like an AC adapter) to see if that helps resolve.