Surface Collision not working with Unreal 5.5 Cloner

I am trying to get my cloner setup in Unreal 5.5 to behave the same as several of the motion graphics Unreal tutorials. The balls should start bouncing off the floor when I turn on “Surface Collision” in the Cloner settings, but

don’t. The balls do bounce off each other if I turn on “Particle Collision Enabled”. I have seen others post the identical problem but have never seen a solution offered. I hope someone knows how to fix this.