Maybe it was a mistake made by a worker filling the bag of red tulips. Maybe they dropped some pink and white bulbs in the bag tagged "red". Maybe. Chances are greater that my red tulips reverted to their original color.
Last year the tulips in my yard were all red in color. Bright red with yellow centers. This year, in the corner of my garden, sprouted pink and white tulips. Tulips, like many other flowers, are bred to enhance a mutated gene's color. I would think red would be dominant and in this case, I would be wrong.
There is another answer - squirrels! Squirrels could have switched bulbs on me. The likelihood of that happening and me winning the Powerball jackpot are one in the same.