Weird brake splatter?

[xdTowMater]

Getting ready to swap pads and fluid on my 08, they’ve haven’t been changed in the ≈20k miles i’ve owned the car, (95k total) and I started noticing this weird brake dust splatter on my front passenger wheel. It doesn’t happen on any of the other wheels and at first i thought it was from a puddle but it keeps coming back. Any ideas?
Thanks
last pic is what the other wheels look like

[nurburgracer]

It could be brake fluid. When you push the pistons of the calliper back in, check for a leak.

[chalbe]

The same thing happened to me in the last two weeks on the same wheel/corner. Stock caliper too. I also noticed more heat coming from the affected corner and brake squealing. Right or wrong I diagnosed it as a seized/frozen caliper. I replaced the caliper and bled the brakes. This solved my problem.

[roastbeef]

its most likley from brake dust adhering better to water spot textures left behind on the "cleaned" wheel you didn't dry.
check the barrels for signs of dampness, but i suspect its dry material mimmicing liquid patterns because it sticks to the texture.

[RocketyMan]

Agreed. It's the brake dust from the pads. This is why I like ceramic pads. Easier on the rotors and less mess on the wheels like this.

I would still check the caliper to see if it's leaking at all. Let us know what you find out!