I do not believe I did anything out of the ordinary that would have caused this to happen. And I don't have a clue has to how to fix it.
If you have a medium mechanical skill, you can remove the metal key from the fob by using a small drill bit to punch the pin out that holds it to the flipper portion of the fob--look at it holding it halfway open.
You can put that same already cut key onto a new fob. The fob is registered with the car's computer by putting a good key in and starting the car. Then OFF. Insert new fob key and rotate to ON. Wait. the Security light will go off and your new fob has been registered to the vehicle.
This is a used but OEM fob that has been reset and ready to be programmed. It's my experience and understanding that once a fob has been programmed it cannot be programmed to a different vehicle unless it has electronically been reset.
I switched my old blade from my damaged original fob with the metal blade on this one. Programmed it to the car and I have a fresh key without having to get the blade cut.
Buy this original new key from this source. Purchase the key cutting service at the same order.
Send a closeup picture of the cut on the blade of your old fob. They'll cut a new one from that
picture. You'll receive a new fob with key blade already in place. The new cut will feel a little rough
when inserting it until the surfaces wear a little.
Key cutting service;
I've bought 3 remotes for my Chevies from these folks. The first was a backup for the Cruze so I could pick it up from the airport to store it or get it serviced while son had flown on business.
Additional info: I did try to buy a used GM from an individual thinking I could crack the case and replace only the case using my electronics from my original and by switching the blade from mine to the replacement. Couldn't crack the case. Save your effort. Just buy from these folks. They work quickly. Mine were out for shipping the next day on the two that needed cutting.
Video showing pin removal. I'd support the blade in a way that the case of the fob is not taking the force. A small hammer or heavier pliers provides enough force to start the pin moving.
Note that one side of the blade has a recess that needs to be positioned for the pin to slide along to hold it in place.