How do I use Anim Graph to modify blendshapes?

I’m unable to modify blendshape values in the anim graph for my character. But for some reason it works fine in an actor blueprint that references the animation blueprint.


This doesn’t work and causes the jaw to always stay closed.





This does work and reduces jaw animation by 50% as expected. Isn't it the same thing as above? Why is the line orange? Is there a better way to achieve this?