Chosen Solution
I’m trying to install a new scissor clip for a A1314 Magic keyboard for my 2013 27" iMac. I’m not sure how stays in place, and it keeps falling out.
The key caps are extremely fragile! Inspect the backside of the key cap review the image in Step 11 in Magic Keyboard Teardown You likely need a new one, here’s one source Apple Magic Keyboard Key Caps