The simplest suggestion I received from Dave S was to pick up a pack of "vacuum caps" at your local parts store. These little rubber ends can add enough bulk to get your plungers to push in adequately when the doors are closed. Door alignment comes into play here as well if not quite right. For example if the rear end of your door looks slightly out of alignment with the rub strips, it might not be clicked down all the way in the latch. Give it a more firm push to find out.
You can also ensure the inside end of the plunger switch is not wobbling around at the fiberglass. It may need to be tightened so it isn't the piece moving. Guys often pull the connector on those switches if the doors are open at car shows and you don't have LEDs and worry about draining your battery. Like you said, easy fix.