I had a problem with water leaking into my closet by the door on the front side (modified Scamp). I caulked and looked and it almost drove me crazy.
The leak was in the junction between the top and bottom halves. The junction was not completely sealed with resin and the
fiberglass mat that holds the two together formed a channel that let the water run to the junction with the door and then leak through a small hole in the mat and behind the Elephant hide Ensolite insulation.
The final fix was to pull that part of the belly band clear and caulk the seam lips AND reinstall the belly band, caulking only the top and leaving a small gap on the bottom for the water that gets behind the band to drain.
Once the water gets into the void formed by the mat and the junction of the top and bottom it can travel from almost anywhere!
Try caulking the TOP only of the belly band and leave the bottom open.