The warn locking action takes place between the plates when the lifting lever rises up on the cam lobe. You will see two flags on the lifting lever that reach into the movement through a slot in the plate. I think the upper flag is the one that will intercept a wheel pin, stopping the wheel until the lifting lever drops off of the cam lobe. I don’t have a movement in front of me but pretty sure that’s what’s going on. Common warn function though.
Take a look at Video Part 3 in the Hermle Course from about 7:16 up through about 10 mins. and you’ll see the flag on the lifting lever. You’ll need a movement in hand to see the actual pin intercept but again normal warn function if I remember correctly.
Hope this helps!
Best, Dean
Best,