I have been struggling with a leak in the back corner on the slide side for over a year. All the caulking looks good and it does not appear to be coming from the slide. I did at one point find a lot of water under the exterior corner seal / d seal strip. I created a 1/8 " drain at the bottom an sealed all the screws. I am thinking of taking the exterior floor and corner seals off and resealing. Both sides had the underfloor insulation removed as it was saturated. I recently just redid the self leveling caulking where the corner meets the top and all that looked good anyway. Kind of at a loss to determine where this water is getting in. The clear caulking around the window looks good but I also wondering it its worth pulling the window and resealing. The wood is not rotten yet but getting close.