Interesting! I've painted lots of houses in fla but have never seen a set up like that. I would assume you are right that they are some type of hurricane storm windows. Look forward to seeing if someone can confirm

Thanks for your response. I added three images. First one shows the inside view of the window with a circle around the area where I noticed the leak. Second one shows the view of the window from outside. Middle one is the stationary window that is showing leaks. Third picture shows the closeup view of the area above window sash from the outside. Notice small mold growth between sash and frame. And it's right below the vent. Forth picture is another closeup view of the area above window sash from the outside. Windows do have weep holes at the bottom. Opening at the top is the small vent which you open and close from inside. Thanks!

Huh! Well I guess the first thing I would suspect is that vent. Maybe it's just the picture, but it almost looks like a louver is missing/broken. If the vent is what's leaking then yeah, I would think that would be a warranty item. Was it a wind driven rain that caused it to leak? And have you gotten on a ladder and checked the bottom of the transom windows above the slider?