Rotten Floor in my Outdoors RV

Yes, While the trailer has been used infrequently as of late, I do regularly inspect inside and out. I have never found a spot that appeared to have missing/worn caulking or seals. RV repair facility confirmed. I am unsure how I could have noticed rotting floor until I stepped on the soft spot. Never a sign of water inside. I understand it is out of warranty and I am on my own. My email to manufacturer was to ask some questions on construction as I could not recall if my walls are wood or aluminum frame, also if they could provide any advice on where to look for leak. Maybe they have had the issue before with the same model and could point out a direction to start. I certainly do not believe it is too much trouble for ORV to respond to my question. I remember when I traded in my 10 year old Jayflight which had never had any issues on my "built tough" Outdoors RV. I bought into the hype that is was a step above the others with regards construction. Maybe it is...However now I have an expensive repair on a relatively new unit. Just needed to vent I guess.