the material on the followers face wears rapidly and can squash the valve top.

no decent supplier will supply a cam alone - you always get:

cam
followers
shells

all 3 normally show some kind of wear or damage.

new followers have a hardened face and are black in colour.

you make out there soft lol , so they updated the followers, when did this happen?
 
Its followers can screw the cam. When you change the cam change the followers for the later black type use ONLY INA brand followers.