No, you were the first reply. We bought this camper in July, and were getting it ready for our first camping trip when I found the soft spot beneath the window. It was hidden by the curtains. (arrow points to soft area inside camper)
We resealed the seams above the window, and went around the window frame with a silicone caulk to seal places that looked like potential leak areas. Then we removed the rubber piece that covered the window frame screws and found three of the screws had rusted out completely. They need to be replaced, but I temporarily covered them with silicone caulk to keep water from coming in because we were getting ready for our first camping trip in it. I believe this is the source of the leak because it has gotten no worse and has somewhat dried out around the interior window framt now. There are weep holes for the water that runs around the window frame, but apparently they had become clogged and the water just sat in the bottom of the frame, rusting out those screws I am guessing.