Update:
The dealer still has my Trail Lite 211S. The service manager told me that he cannot figure out how the factory expected the slide to seal in the out position. He is dialoguing with the factory on a seal that is used on larger RVision motorhomes, and he believes will work. He said that a new 211S on the lot also leaked during the recent rains! If you have a slide model - water test it with the slide in and out, and don't forget. I was getting moisture inside even when the roof AC was running for an extended period of time, and drained onto the slide, so even if you don't plan to leave it extended in a rainstorm, make sure you check that out!