KinematicBody2D does not detect rear-end collisions

Question

Sorry if something is not understood, I use a translator for this.

The problem I have is that I have 2 kinematic bodies that are balls, when one moves in one direction and the other hits it from behind, only the one who hit it from behind will receive the collision instead of both receiving it-.

Answer 1

That's the problem, you used KinematicBody2D. Kinematic body doesn't send a collision back, what you would need is to make them RigidBody2D instead, because (like it says) RigidBody2D is completely affected by 2D physics.
It works more like Newtonian physics, "For every action, there is an equal and opposite reaction".