Travel trailer uneven Tire Wear

Well Kenny mustn’t be too worried ‘bout this…

And to add, you need to provide much more info and context. We’ve given you a plethora of information based on most likely scenarios with almost zero context. 

I had that happen a couple years ago on my 5th, but it was one tire that the outside edge wore out of the 4, turned out to be a tire defect.  

I would be with Grit on this one, one spring that is failed would throw make the rv lean a bit but the tires and axels would be the same relation to the ground. 

what I would do is change the tires to opposite sides, if the tires if it is still in usable condition.  watch it over your next trips to about the same distance and see if the issue now pops up on the new tire.  if it doesn't then it may have been a bad tire, if it does then you need to look at your axel and spindle relation ship, and see if the axel has been bent to see if you can get a proper alignment, or new axel.  it could also be a loading issue but that would be my last though as that should just be hard on the whole tire not the one edge.  

another thing to note was the air pressure in the tires, was it properly inflated and so on.  and last but not least is the road condition.  if you drive on a lot of ashfault roads and the big rigs have cut tire trailes into them, is that tire riding for a long time on the edge of the tire swale due to your driving position on the road.  I have seen that take out more than one tire fairly quickly. 

 Not likely a flat spring would induce great outer tread wear or any at all. Axle should be true and square. Worn spring would just make the trailer lean to the right. 
you’ve replaced the springs a year ago and one “failed”?  Also not super likely. Although maybe you put 30k miles on the camper with an extra 1000lbs on the R side?

Regardless, the issue is likely an axle issue. Not square to the world F to R, camber issue (usually inside wear if they lose camber, or a toe issue (bent or not welded square to the axle tube and toeing “in.”)

Ive seen the latter many times on different trailers where the spindle isn’t quite square to the axle.  There is not a fix for this aside from replacing the axle.  
That said you don’t say how many miles it took to achieve this tire wear but if it’s not super aggressively wearing, I’d just swap tires side to side or flip the tire on the rim and keep motoring.  Less costly and intrusive if you can get a year or 2 out of tire swapping and it’s not causing other issues.  Had a boat trailer like this once.  Tires only good for 4-5 years anyway based on age and it would take a couple few thousand miles to show visible wear.  With 4 tries to choose from, 5 with a spare, it wasn’t worth fixing when I could just swap 2 tires around once a year and never wear one out  

And fwiw, not a TT expert but a few years ago when we bought a Toyhauler, the FR Cherokee models were the most absolute cheap low end quality of all the ones I looked at.  There may be cheaper/worse ones but if they are it couldn’t be by much.  Not being a smart SS​, just an honest observation  

I believe I may have found the culprit my curbside leaf spring is flat as a pancake, appears to have failed. Less than a year old  purchased through  E-trailer from Dexter.

That type if tire wear is usually a camber related issue (provided PSI is correct). Are you sure your axle isn't out of alignment?