As 1911 explained the problem might be that the mag spring is still too stiff. A way to test this problem is to
put only a couple of bullets in the new magazine and shoot the gun. If it fires without a problem reload the
mag with as many bullets as it's suppose to hold and fire it again. If it jams or FTE you know what the
problem is. I just witnessed the same problem at the range. The guy next to me was having all kinds of problems with his new Glock 17. As soon as he removed the top three rounds the jamming problem was solved.
This is a guess. If it was me I would have sent it back to the factory. That the point of a lifetime warranty.