It's hard to tell from the photo where that is in the camper. I can tell you that when our Zinger was brand new last year, I had a small puddle of water on the night stand next to the bed after a day of constant rain. The night stand is in the corner of the front and side wall of the trailer.
Upon inspecting the outside corner molding I found this:
That void was almost directly in the same spot as the night stand. Water was coming in, running down the inside paneling onto the night stand.
A touch up with clear ProFlex fixed it right up and it has been water tight since.
Look for voids in the caulking on the corner molding from the roof to the bottom of the trailer.