I have never had a leaning problem but I would question it too.
I would take a good look at the suspension maybe even raise it off the ground and be sure nothing is wrong. Then I would take some measurements and call the service center and if they say, ďitís normalĒ. I would fallow up with an E-mail so itís documented.
If you plan on doing some traveling an evenly weighted trailer is optimum. A poorly loaded trailer could/should tow poorly(sway/bounce weird) and this could be more prominent at certain speeds or conditions. If you have brakes they could perform differently(especially on wet pavement). Tires will wear differently, bearings might have issues.
Maybe you can load the trailer to minimize weight difference and I hate to say it but there is probably no better way than to put some miles on, safely. Even if it tows true I would put my hand on the hubs when I stopped to see if they are hotter or overly hot on one side(I do this often on all of my trailers, hopefully it will prevent a catastrophic failure, only takes a few second.)
The right thing to do is load trailer just like youíll use it and have it weighed. I am sure there are standard numbers for weight: 10-15% on tongue and as a GUESS 0-15% side to side
Camping is supposed to be relaxing so itís good to solve all your issues before getting on the road.