actually to pull the arm back, you have to loosen the 2 bolts behind the LCA mount, so you can pull some shims out, then tighten the 2 bolts to move the LCA "stop" rearwards. This will then allow you to slide the LCA rearward.
The only thing that holds the LCA from sliding forward (like in the OP) is the clamp load of the nut/bolt. I'm not sure of the torque spec, but check the nut, see if its loose. I'd crank it down a little and not worry about it.
