Strange reaction branch?

Hello, I am playing with the physics of material and what I am doing is that when one of the tires of my vehicle stepped on a Physc material adds a sound effect, what happens is that it works, but strangely that is, when this in false and then in true nothing happens, but when it becomes false again then the sound effect appears that is to say you have to wait> False> True> false to be able to apply the sound, Here I leave all the blueprint and video how Does it work … Any suggestions? Video : - YouTube