I contacted Ron Carter, Kichler's Corporate Trainer, to get the low-down on this issue. Here is what his answers were:
Why is it that the 15711 starts to rust in areas where chlorine / bromine is used?
It doesnít rust from the chlorine/bromine, it turns white/crusty.
When it rusted, it was from a slight, harmless electrical charge created from the internal riveting process used during manufacturing. That spread from the inside outward. We are past that now as that process has been corrected in manufacturing.
So it sounds like there was an issue in manufacturing that has now been fixed. And knowing that Kichler has an outstanding counter-swap warranty, if I were you I'd get together with my Kichler rep. and make sure to get these fixtures replaced on warranty - but not just with whatever fixtures your branch has on the shelf. Make sure that the replacements you get were made AFTER this manufacturing problem was fixed. That way you don't have this happen again.
And it sounds like you can expect some white/crusty matter on the light as a result of the chlorine/bromine as well. But you shouldn't get any more rust, with the new ones.
By the way, Ron Carter isn't just the corporate trainer. He's also the engineer who designed the majority of the Design Pro LED fixtures. Smart guy. If you ever get a chance to go to one of his training sessions - do it! He's a wealth of knowledge and is a heck of a nice guy too. After the class, I went out to dinner with everyone from Kichler, including Ron, and got a chance to know him better. Great guy.