Hi, all. When I got my Gemini a few days ago, I thought I'd have to send it back--the "f" key either didn't register, or wouldn't stop typing ffffffff. I got brave and pulled off the keycap, and found that the problem was the rubber ring tended to get stuck on one side when pressed.
I tugged at it and stretched it and eventually got the key to more or less work, but it was still extremely wobbly. Then I figured out a real fix: I dabbed the ring with WD40, which lubricated it and got it working reliably.
As others have mentioned, you should pull keycaps off from the back edge to avoid damage.
--Harry