It is not the switch that is the problem. The problem is that the plastic body of your G36 has been worn down by the much harder metal ball bearing. The area the ball rides in has been leveled out by the ball. Because of this the divits are not as deep as they used to be causing your problem.
How to fix it?
Like Jtf2 said, take a dremal and CAREFULLY deepen the hole. This should solve your problem