I have never seen the module in question, however switch pops are always due to the circuit design. Whenever something something being toggled by a switch pops, you are hearing the rapid charging of something being connected to ground that did not have any previous electrical reference. There are several better ways to design such a circuit. to prevent audible pops. The most common being to shunt a very high impedance ground reference. This prevents an immediate complete charge by providing a slight current path while the switch is off. An example of this in a stock module would be the Bright (or Gain Boost) found on every module in it's stock form. A 10M resistor prevents any sudden charge that could potentially cause a pop. NOt so much of an issue on a Bright circuit, but the potential is there is a Gain Boost is present.
Hope that helps,
Rob