Unstable collision detecting

I have simple blueprint that deletes a cube when it touches any object. But this only works with objects that move (like a character). If the object is static (a standing character or cubes below it), then the falling cubes ignore it. But sometimes, it can work for a standing character with a delay, at a height of 2/3 of the body. I don’t understand why this is so. Can you tell me how to fix it?

(sorry for links, for some reason links from imgur give out errors)