In Blender Game Engine, version 2.79, an object has a test Keyboard sensor, with an And controller, that activates an Edit Object actuator to add an object. This works fine. However, when I added a Ray sensor, the same actuator now adds three copies of the new object instead of one. This should a forteriori add one or zero objects, because it is the same logic plus requiring the Ray sensor. So why is it adding three objects at a time?