I am of the opinion, that the manufactures build to the cheap side of the product.
We have a 2012 Sunset Trail BH the first year (2012/13), bought in the spring of 2012 used that year, in the spring of 2013 took it in due to tire wear and appearance of a strange looking stance, tires looked funny.
The axels were bent out of specs, I had it tested at an independent frame shop, they came up with similar numbers that the dealer came up with.
Same issue 3000# axels on a trailer that weighs 6800# empty. Dealer would do nothing, Lippert said the axels were 2 years old from date of manufacturer. After much whining and complaining, Lippert sent axels, only, no brakes, no mounts only the axels, by that time I had #3500 axels installed, could not go any higher without changing mounting system.
3 new tires, 1 at a time, due to 2 flats and a blow-out on the highway, some say the tires a from China, I can not confirm as All have been replaced done within 5800 miles over 2 years.
These were "C", I think, rated tires, decided to replace all tires, tire shop said I should have at least "D" rated tires, the tire tech said I should have gone for "E" rating.
All in all cheap inferior products used due to cost. Good luck with your unit.