I have a Shield and it works with either mag identically.
Being as yours doesn't I would consider it defective. You might be able to live with it today, but who knows what collateral damage it will have down the road.
Your attempt to fix it yourself may've caused some warranty issues, though.
Smith has an excellent, documented track record of fixing issues with quick turnaround. I bought a new Smith 1911 and had extraction issues right out of the box. Called customer service, they issued a FedEx call tag and the gun gone less than two weeks, door to door.
Finally, while others are quick to pass judgement, I could care less. It's your gun.