I have seen vinyl racing stripes do that so I guess leaching is possible
What year is the car?
Makers have been dropping the thickness of the clearcoat year after year to some absolutely insane thin measurements and this has to have some long term effects
I have only worked on a couple of Hyundais and as I remember the paint is typically Asian, on the softer side of the spectrum
I really wish I was there and could assess the paint in person
Clear coat failure can look similar to that and I hope that's not what has taken place
I would love to decon the paint, clay it, and hit it with a superfine finishing polish and see what happens, and then make adjustments in product, pad, and process to try and even it out