i have similar rusting yellow spots on rotor only 4K ,2021 elantra model
taking it to service to see whats going on
Some parts of the rotor don’t come in contact w/the pads, and there it’s normal for rust spots. If there’s rust spots on the rotor in the pad area, and you drive the car daily, your plan to have a shop check it out is a good one.
Rotors are bare cast iron. It must be bare where the brakes touch to work properly. Iron rusts. These are facts of life.
What you see is normal.
Tester