Found a problem….
The extruder mount slips on the X carriage if it hits something like a warped hole overhang. Which really it is okay to prevent extruder damage but it just slips a little too easy.
I made it hoping the extrusion lines would line up like Velcro and keep it in place really well, not so much. So I can try just making the mount thicker, with a but more overlap on the back and maybe a little taller (wider). If that doesn’t work, add a screw (last resort).