That's the exact same thing that happened to me. I think it rolled against the boat while handing off or I pressed it with my hand while hooking my lanyard up. At any rate, now I know that those top buttons can turn and lock in place, so I'll keep an eye out and know that you just have to rotate it square to fix it. I was thankful that the camera would still shoot with the button depressed. I think there's actually a setting for that on the custom settings menu. I have to spend some serious time reading my camera manual so I can set custom menus for underwater like I have on my little Oly.