[tentcamper]

Yes that looks like a very odd wear. Like the camber or toe on the axle is off. But maybe its from a belt shifting and the tire became deformed. If you have not noticed the wear before it most likely not an issue. The tire just became deformed. But keep an eye on it. Any sings of it wearing on the outside I would have it into a trailer/truck shop for an alignment check.

PS, I also went to the endurance tires. My tire dealer a national chain stocks one brand of ST tires for each size. They can get other brand from the warehouse in one day. They indicated that for my size tire they switch from the Carlise to the GY endurance. Their comment was that everything they have seen the endurance is so over built. I hope they are right.