Water leaks can be major problems, or not. We were fortunate to find our problem before any major damage was done, but if we had not parked on a slope causing a scary amount of water to run out of the belly we might not have found the leak.
Ours turned out to be 2 cracked elbow fittings on the back side of the UDC although we also had a couple of loose fittings. We did not find it during our PDI, but being do-it-yourselfers we just jumped in and starting checking the entire plumbing systems.
We ended up dropping the coroplast, pulling out 30 pounds of dripping insulation, drying it out, and replacing the insulation. Was it expensive - no - less than $50 for new insulation. Was it time-consuming - yes - but now we know it is fixed and we learned a lot about where things are below the floor.
Friends ask why we didn't go back to the dealer, we wanted to know it was fixed correctly and that the cracked fittings were the original source of the leak.
To the OP, I agree these things should not happen on a new unit, but %#$ happens. Just get it fixed and enjoy it or trade it and get something else, life is too short.