If you took off DZ in the COP most likely would fault.
While you're in there, check your 5 & 12 volts.
Should read 5.1 and somewhere around 10.75.

Back to your original post, you said the car would run up, seemingly not recognizing the slowdown switches when they opened correct?
Maybe the cam is passing the switches, but not opening them on occasion, then seeing the mag switches, which is a fault.
Does the car cam appear plumb? The approximate distance between the cam face and switch body when opened is like 1/4" if I remember right.
Also, upon hatch switch inspection, did you look at each spring steel plate for breaks?