Just to be sure I’m clear, the black mark between the sensor and the ruler is where the sensor should move to?
Here is a new copy of the right hand board fully routed (still needs some of the traces straightened but other wise ready to go). You should verify the sensor is in the correct direction when installed according to the diagram (i.e. with the beveled edges outwards) to make sure we have the orientation correct.
accordion-right-hand-Sketch.fzz (182.3 KB)