Swim Platform Rust Stain Issues

[IOLANI]

My gut feeling after looking at it some more is that the 2 SS replacement brackets are what's rusting and causing the issue. I believe the bolts are already high grade 316 which is why none of the others are bleeding rust. I think the rust is forming on top of the flat part of the bracket and the bolt is simply acting as a conduit for the iron particles to creep through the bolt hole to the top of the platform. I can almost guarantee you put those same bolts in a bronze bracket the rust will cease to exist. Replace the bolts with new 316 bolts and the same thing will happen, the rust will return.

All that rust on the bottom of the platform didn't come from that 1/2" bolt.

I could be wrong, but I don't think so.