While I was out shooting this past week, I noticed that the Mega OIS switch had popped-up from the barrel of the lens. I took a closer look and found that the lower edge of the switch had cracked around the tab that attaches it to the lens barrel. Unfortunately, that is the only thing holding the switch to the lens, and it can easily pop all the way out (only tethered by the wires). I used a rubber band around the lens to keep the switch in place. I will probably super-glue the switch, because the crack is so clean that it is almost impossible to see, when the two pieces are held together. I have absolutely no clue as to how, or when, this happened.