Hi, Chris
In the brake-out board manual thy talk about npn & pnp sensors.
NPN Inductive Proximity Sensor
NOTE: The break-out board was designed to use either NPN inductive proximity sensors.
A PNP inductive proximity sensor can be made to work by placing a 1K resistor across the signal and ground screw terminals.
Might try this, Chip
RC, I agree with your comment above