I have the same situation on my 5th wheel toyhauler. I asked the dealer to adjust it when it was still under the manufacturers warranty but was told that if didn't leak, adjusting it could possibly cause it to leak. They would have tried to adjust it if I had pushed the issue but told me that their past experiences with similar slide adjustments had not gone well. I went along with not having it adjusted and have never had any problems. Cosmetically it doesn't look quite right when you look at from the rear but so far, so good.
