You nay have some cross pollination and might have come up with a new flower! Thats my unprofessional opinion ;o)

I like a pink tinge to my flowers. Could be nutrients, could be level of sun they are getting that make them slightly different than the package.

I have 3 tubers of the same variey planted in 3 very different places in the yard this year to see how each turns out. One is in a new bed without too much soil amendment, two are in an established bed but with different sun exposure.

A lot of dahlias are blends of 2 or more colors. If you have a pink tinge it could be your soil or it could be you didn't get the dahlia you were told you got.

Hi,
I have recently read something about plants that are planted toghether they can change color and it is called a sport. I think it has something to do with roots touching. Could this be in your case?
As an example a month ago I planted in pots some purple violets and some yellow violets, about two weeks later I noticed that the yellow violets had purple streaks in them they formed a sport.
But Dahlias are hybrids so it could just be a that. I have a Dahlia Linda it blooms yellow but I noticed that one flower had a purple spot on it like someone dropped some ink on it and it ran. It was pretty cool looking. I think it happened because it is a hybrid.
I bet yours are pretty Dahlias!
Happy Gardening,
Laura