We had some strange tire wear, but ours was on the inside edge, and not all the way around. Originally I thought it was a bad tire. I was unimpressed with my dealer's assessment of the frame and axles: "No issues noted" was the comment.
But then at a campsite, we noticed the rig leaning to the off-door side (3 slides on that side). Also the tires seemed closer together on that side. We took it to a Big-Rig trailer shop, they told us our springs were undersized for the weight, and flatter on that side than they should be. Out of warranty, so we replaced all 4 (4-stack) with 6-stack 3300lb springs, new u-bolts and shackles. Rig sits like it did when new, pulls better and tires are aligned.
E