Yes, even my two units of S9 developed similar issue. As time passed display tuned yellowish. Samsung asked me to change the motherboard at Rs 17,000 for each phone. Never repaired them as was a waste of money.
I think they are forced via software update or quality in itself has been poor. If you search this forum you will find complaints of similar nature.
Same thing is happening currently with my S10 lite. Black color is shown as greyish red now. Its like back light is leaking or something like that. Service center quoted about 11.5k to replace the display. Ain't going to waste money on that now.
We apologize for your inconvenience. We request you to kindly visit the service center for a physical inspection of your device. You can locate your nearest service center with this given link: https://www.samsung.com/in/support/service-center/
