Thanks everyone for your comments.
The stains did not happen from this last wash (when the pics were taken) - it was from some previous time, and I see stains on the rims of our other car as well (was not washed this last time). On the other car, most of it comes out with some Fine Cut Cleaner by hand with a sponge (but not all of it).
I don't think heat was an issue - I wash in the morning and don't do much car work in the direct sunlight.
With the pics - I washed that morning and the pics were taken late afternoon, so I think the rust on the rotors is from sitting all day after being wet.
I've used the wheel cleaner multiple time before without a problem. I guess I left it on too long one day. I didn't know it could cause that much damage.
What I used when this happened: Black Magic No Scrub Wheel Cleaner.
What I just started using as of this last wash: Griot's Garage HD Wheel Cleaner
Is the Griots more mild? Yes I will definitely be paying attention to dwell time now.
As for the rims in the pics, I don't think I am going to mess with them any more myself - the issue is very slight, and I don't want to mess them up worse than they are.
Attachment 48853Attachment 48854
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