My 12.9” iPad Pro is slightly uneven at the LTE antenna line. I checked using a steel scale. The bend is smaller than Apple’s 400 micron tolerance so it is within their stated specifications.
Wouldn’t have been able to verify without a steel scale. It’s definitely much less of a bend than other pictures in this thread, which seem to be bent around the microphone port.
I’ve owned (3) this is how all of them are. All of mine were cellular too, my latest 11” being the 1TB version is the exact same way. They look straight, lay perfectly flat face down. Staring down the edge is the only real way to hardly notice this. Although, I’d say my current 1TB is honestly just about perfect “best I’ve seen”. Anyways, any bending on the side long ways is most likely user induced.