I used to watch the Pippi Longstocking movie when I was little. I noticed even then this obvious change. If anyone else has seen the movie, you've probably noticed this.

In the song when Pippi is singing about how school is totally pointless, the other kids get up and start cheering and holding her above their head. I think she says "Plutification" her weird way of saying multiplication and her hair is dark brown. It is usually bright orange. To this day, I don't know what happened.