The Procedural Aiming aligns the sights to the camera which is attached to the head bone, in the case of true first person. Because of that, the camera doesn’t change position in relation to the head bone and thus the code only grabs the camera position once at the start, instead of every frame.
If you don’t attach the camera to the bone anymore (which is what you’re doing, right?), then you’ll need to grab the position of the camera every frame (or tick) so you can align the sights to it. You’ll also need to change the space, since we were using the head bone space originally but now you’ll need to use world space.