My wagon glass is possessed as well, the latch releasing itself over and over while the car is parked in the garage. In fact, I just heard it go off half a dozen times as I started typing this. My remote will unlatch the glass when I want to open it, but the button itself stopped opening the glass a few months ago.
Can you explain how/where you "pried off the cover on the button/handle"? I'm not seeing any way to do this. I've had the whole assembly off the car but didn't see a way to open the actual switch housing itself.