Ours is the model 355LS which was a short lived floor plan and now discontinued. I think it was brought out just ahead of it's time, as now a few of the upper line manufactures now offer this plan.
Forest River Wildcat 353LS-OK Fifth Wheel
On the non curb side just ahead of the rear top corner of the slide as per design was a cross brace in the aluminum studs of the trailer wall. However this cross brace did not extend all the way to the next stud, only out far enough to allow some surface support to the exterior wall structure to adhere to. However with normal flex of the frame and walls, and being at a point were the largest slide out was mounted this caused the fiberglass to crack approx. 6".
I kind of figured FR would tell my local dealer to cut a hole take care of the problem, patch the hole, paint it and send me on my way.
But, instead FR asked me to send a couple of photos to them via the internet and then told me it would have to come back to Elkhart to be fixed right. That this would involve removal of the slide outs as well as the complete exterior skin on that side of the trailer.
I asked if it would be ok to use for a few months before sending it north, I also laid a bead of silicone over the crack to keep out any moisture in the mean time. My thoughts were to send it up in July and August, the summer months in Texas are not the more enjoyable time of year to camp anyway. We worked out a time right around the 4th of July and we hauled it up even though they offered to pick it up. We made a little camping trip out of it and I wanted to meet the gentleman who was on the other end of all the phone calls. I was also told to make a list of everything else that we had noticed that needed attention and they would handle everything we could think of. One of the things on my list was that the material on the underside of the trailer had been cut and taped over a few times I guess at the dealership and was looking kind of crappy. I was told that they would clean things up underneath. Rather than clean it up they replaced it from one end to the other. They also repainted the front cap due to the chaulking of the finish. Another complaint we mentioned was the inability to keep a constant temp with the tankless water heater in hot weather climates. After a few conversations they offered to do an update that the tankless water heater company recommended or replace it with a new gas/electric water heater which is what we did.
And yes, it was right when it came back. Now I have found a couple of little things we had missed earlier, but then we also took out the second year warranty from FR so I have a year yet to go for those repairs.