So I'm back to doing a Pi Hat, using the template. I'm running into the alignment issue I had before where the unit clips the side of a hole while probing. The symptom last time was I killed a nozzle because the probing worked as the alignment was sufficiently off that the nozzle clipped the edge of the hole.
But now, no matter how precisely I align, it dies in the probing phase:
You can see that when it intended to measure just to the left of the hole, it went a smidgen too far right, dove into the hole, then zoomed sideways digging a scar across the board. It then dies on an error (the Z probe is triggered when it shouldn't be).
I also notice that as I probe around, the alignment can be off by as much as a 1/4 diameter of a through-hole. I've tried being ultra-precise, using different alignment pads (even aligning to the "problem" hole), making sure there's no warp in the clamping, etc.
For reference, here's the circuit:
It's carving a scar where that trace is on the lower-right. On one alignment-check pass I've noticed that the bottom of the vertical header can be noticeably more misaligned than the top, for what that's worth.
My X-axis backlash is zeroed out, as the test print doesn't indicate any. For reference: