I’m not bothered by it. I think it’s an opportunity for children to create change and continue using a play material even if it isn’t it’s “perfect” clear colour.
If you would like to relax into mixed colours I suggest you try primary to secondary colours as it mixes up to an actual identifiable colour instead of murky swap colour.
Talking of which… Here’s her murky swap monster.
Scented dough? Add an essence
Preschool playdough recipe… I often halve it. Add more flour if sticky (or add the water gradually). Colour the water.