This might be a bug, I am new and don't really understand how everything works yet.
My problem is the bounding box on the platform is set to rotate with the layer using left/right/up/down which is does. You can see it with the red box falling on to the platform as the platform rotates. However the ball that is on another layer falls to where the platform first starts and doesn't fall if the layer/platform has been removed from under it.
Best way to see it is hold down the right arrow key and refresh the browser window.