That is a good question. And the answer I’ve deduced is it’s simply whichever tomato they use. I’ve had pinkish tomatoes before and blended them up for salsa or sauce and it stays more pinkish. Part of it is a color change from cooking, breaking down certain molecules, so it makes some sense the color changes. But a lot of popular tomatoes are orangish on maturity. Also depends on the rest of the soup. I say as a gardener/amatuer cook/full time autist