Wear on both edges

[Sundown08]

Hi Everyone:

We picked up our new 2015 Big Sky 379RL last Saturday. I was so busy during the PDI that I forgot to crawl underneath and check things. The next day I noticed that all of the tires on the trailer including the spare are worn on both the inside and outside edges. I have contacted the dealer and sent them pictures. I expect them to replace all of the tires. My question is what would cause this kind of unusual wear? Any help or suggestions would be very much appreciated.

Thank you,

Steve