You can confirm it by installing a second screen protector...it should lift in the same location. I highly doubt that Apple will swap the phone. Basically, not all screens are perfectly flat due to the curved edge on it. Some are worse than others. I don't know how they make this, but if they are using molds, that would explain it as they can be imperfect. More than likely, it starts flat and heat is used to mold the glass, but as it cools, the glass will warp a little. This happens with metals and wood as well.
edit: You can look at your screen or put it on a flat surface, but the warping of the flat part of the screen is almost undetectable except by placing a flat piece of glass with adhesion on it. It will look like exactly what you see with a glass screen protector.
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Get a clamping case to use for a while. Glass is actually a amorphous solid (think liquid properties) so while the case will resolve the left for the short term, over time, then glass will actually mold to fit the screen better.