The new factory "fix" for rot in the subfloor is to coat the edges back about 6-8 inches top, edge and bottom with some kind of sealer on the plywood. Then I think they have put some drains in the C channel to keep it from becoming a water intrusion source (but I am not completely clear on that).
The problem with all of this is that in the efforts to keep the water out of the subfloor, they insure that it will not dry out either, if it does get in. Over many years of observation, I have noted that best efforts to keep water out fail, and the water that gets in becomes trapped, not drying out. I have had "water resistant" watches which once breached, with a tiny amount of moisture, continue to have condensation inside... The water got in, but now won't go out.
My 2014 FC 20 appears to have the vinyl flooring go all the way to the edges of the trailer, even under the cabinets and bed and dinette area. That severely limits the ability to dry upward if any water breaches the defenses into the trailer. In all my old trailers built in the carpet era, the carpet did not go under the cabinets, or was loosely laid scraps inside the bottom against the floors. That allowed drying from the top and I have seen very little evidence of sub floor rot in most of the trailers I have owned. The exceptions were the '54 22' whale tail and the '60 22' (rare) star liner I once had.
I recently purchased and tested a new non contact (no probes needed) moisture meter which I reported on in another thread. I plan to use that often to check the floor moisture on my new FC. I have also thought about cutting back the vinyl flooring under the cabinets so the floor can dry upwards. Unfortunately, I think the vinyl even goes under the shower and in that area there is absolutely no way to either remove the vinyl or measure for any moisture leaks as there is no access at all to that section of the trailer.
The factory, and many others, are guilty of thinking of one way water movement, that is to keep it out. The real key is to understand you can't keep it out completely and forever, and design a system which will allow it to dry out, when it eventually does get wet. Many, if not most systems to keep water out also are very effective in keeping it in too. That is the worst thing that can be done.