There is nothing you can do to correct this - short of replacing the C pillar window and the chemical reaction damage-prone trim that comes as part of that glue-in assembly.
Then either coating or wrapping it and stopping all use or exposure to whatever caused the bleed to begin with.
The issue has now been confirmed on both silver/brushed metal/adonized/chrome and black trim so it is inherent to a. material used b. external factors that lead to the damage.
I have been lucky not to have this issue creep up on my early production 2018, nearly 3 years in and countless handwashes (by me and others) in.
But that doesnt mean anything... one wrong use of a carwash shampoo or car cleaning product with the wrong pH and its done.