Samsung recently posted an article explaining the hows and whys of One UI. Eagle-eyed Reddit user qgtx spotted that one of the images has a punch hole selfie camera. Oops.
Samsung has since updated the article with a new image, but that one is quite interesting too gone is the camera and the bezels got thicker too.
Here are the two images side by side:
Original image New image Bezel comparison
Of course, this article is mainly about the software and the shape of the phone is meant to be generic (many Galaxy phones will run One UI, not just the flagships). You can even see that the selfie camera disappears when the screen turns on.
Still, this looks like some of the Samsung Galaxy S10 promo renderings slipped out.