The reason for that is this: Different basses display faults in technique more that others. You can't get away with playing loosely on an MTD six-string the way you might on a P-bass with flatwounds. I've experienced that "click" that you have before. My initial resolve for it was to lower my pickups. Then, as I realized that I wanted my pickups higher up, I needed to clean up my technique to rid myself of the problem. Pushing down on the strings too hard, a poorly executed attack (particularly when using a pick), or letting your fingernail or the bony tips of your fingers can all lead to it.