What causes a tire wave

While doing weekly maintenance I noticed an odd distortion on the tire. Kind of a wave. I cannot feel it, probably because it does not rise causing a bump, just a wave.

I'm going to order a new tire to be safe, but curious on what happened under the surface and is it just a manufacturing defect or something with the mounting.? The tire has been mounted for about 930 miles and it just happened in the past 100 miles.