I just checked mine and there is only one click when the rear trigger is set. The screw that the yellow arrow points to does what VAN shows in the picture above. As he said, turning it in, CW, takes some pressure off the heel of the rear trigger. If I understand the mechanics correctly, the rear trigger's blade should not be able to touch the sear arm unless the front trigger is pulled and held rearward. Otherwise the gun could be fired by the rear trigger alone.
OK, can't get the picture to load, but it is the buggered screw right behind the rear trigger, looking from the trigger guard side of the trigger plate.
I think the picture you show of the state of the triggers at the ' 1 click ' position is the correct state at rest, so whatever is allowing the rear trigger blade to move past that position, the 'click' - that is the problem. I see marks by the front trigger spring, maybe it is not doing it's job correctly?
