@o_lampe said in Very! strange height map results:
I'd check the drag-chain if it causes the BLTouch mount bending/tilting.
It uses the E3D spring trip arrangements to hold the cables as upright loops, so any "pull " is consistently towards the front centre.
Nothing was moving much or retaining any offset when I was deliberately trying to create head<>rail movements & the BLTouch is attached directly and rigidly to the underside of the printed cap I had the dial gauge on.
I'll do more measurements and gauge tests when I get chance.
I'll also try running heightmap with a tool on the head - the Hemera Direct tools are quite heavy and should produce a change if anything is loose anywhere.