The Makita router used before the spindle was installed is not grounded. Therefor the magnet is required with the probe for it to work correctly.
The PWN spindle IS grounded, as it should be.
When the PWN spindle was installed the probe didn’t work correctly. During the “probe check” procedure, as soon as the magnet was attached to the spindle, the probing completed without ever touching the plate to the spindle. That prevented the probing from completing correctly. It seems that the way the cable to the probe is wired, it doesn’t work with grounded spindles. The fix was to reverse the wires…in other words, the wire going to the magnet needs to be attached to the probe plate