The clicking you're hearing is likely the U-channels on the T-20 clicking against the case as you pull the top plungers out. The U-channels almost never ride directly on the case, and you have to push the lower plungers in (by pulling the levers back) in order to start to pull the uppers out. There's almost always a point where the resistance changes, and the channels plunk against the case, and acting as the fulcrum to pull the upper plungers out.

It's not a problem as long as this is what it is... My darn RIM and Huslter do it. It's annoying, but doesn't harm anything to my knowledge.