Copies of the same sprite are called instances in Construct. Events like "Mouse On Object Clicked" will pick the clicked instance. And any actions inside this event will only apply to the picked instance.
In your project you need to move events 17-21 inside the event 16 (make them sub-events).
Also, I suppose your couleur variable should be an instance variable on the Spot sprite. This way each instance of the Spot sprite will store its own couleur value