If that's the worst problem you've found with this camper you're doing well.
My sister turned on the water pump in their brand new travel trailer on the first trip out and it happily pumped a couple gallons of water out on the floor before they realized what was going on.
The RV manufacturing industry in general is sloppy and known for cutting corners to crank out as many units for the lowest cost.
Unless the camper is sitting perfectly on the jacks, there is going to be a little twist in the body of the camper. Some twist more than others, such as my Palomino which twists a LOT, to the point where the door will pop open if you get too far out of whack. Your host is probably pretty rigid but still twists a little.
That's why adjusting the right rear jack moves the lock plate enough to latch. Sometimes you're twisted one way, so you have to raise the jack. Sometimes you're twisted the other way, so you have to lower the jack. You could achieve the same result with the left rear jack.
However if this is a problem with the camper in the truck, all jacks raised, then you need to adjust the striker plate to make it work.
Should it have come from the factory working for what you paid? Sure, but most RVers have come to realize that perfection is never going to happen and take minor issues like this in stride, rather than quibble with the RV dealer over warranty, spending way more in time and fuel than the repair would cost.
Someone could make a perfect camper if they wanted to, but it would cost more than the rest, and people will gravitate to the cheaper alternatives. Seems most would rather complain that their cheap camper isn't perfect rather than buy a more expensive one that is.