Looks like the rotating reluctor tabs rubbed up against the bases of the sensor rather than hitting the sensor fins. If you look at this pic you can see gouges where it rubbed right in between where the 2 fins would have been for the sensor, could have hit the fins too but hard to tell since they are gone. Sensor felt tight so don't think it came loose. New one I'll leave a little more clearance for the tabs sitting too deep in the fins in case the crank is walking back a little..maybe thrust bearing wear.

