Yeah, In My Humble Opinion (IMHO) you have the same problem I have had on my 2009 BHDS Jayco. You are getting moisture behind your siding. Determining from where is the problem. I have had 2 areas (entire left front side wood support structure rot and left front lower corner of slide out. The answer is replacement of wood supports and corroded metal.
Jayco's 1st line of defense is that you haven't done your required caulking and there is no out of warranty support. Don't buy it. I bought my trailer new in Feb 2010 and my dealer (after I didn't accept Jayco's initial denial of Out of Warranty, no support) assisted me with Jayco in arranging an In Plant Repair during Jul 2013 at their facility in Middleburg near Elkhart, IN. As a Goodwill guester, Jayco rebuilt the front of my trailer and replaced a defective
Motor/Actautor on my rear slide. The only hook was my expense of taking the trailer to IN and dropping it for approx 3 weeks and then going back to pick it up (approx 750 miles) each trip.
Over all it was a pleasant experience and Jayco treated us very nicely.