My FW was 14 years old and had very little use when I bought it. When I started using it 7 months a year I noticed a window leak at the dinette. I removed the window and found that they had partially missed the hole when they applied the putty tape. I installed new putty and used proflex around all the windows.
I also sealed the top and sides of the marker lights as they were developing water stains inside from water weeping in. If the water leaks in fast enough it will flow through the center hole and go into the wall cavity.
As I have read posts on here over the last few years it seems common for people to have rotted out areas after 3 or 4 years. It's probably not that they got to that age and just started leaking, they were leaking all along and the damage is now evident. The manufacturer has failed you. There is a good chance the dealer could fail you so before I would risk ending up being one of those people on here in 3 or 4 years I would go over every inch of it and seal as needed.
If you take it in to the dealer I would then go over everything when they were done! If you dont get this nailed down, you will be the one with a rotted out rig and all they will say is it's out of warr and you didn't maintain it. I now remember one of the reasons I bought used.
