Has nothing to do with colors, but instead blurring/fronting
You know White Surprise Airheads, and how theyre made when they switch from one flavor to another in the machines, with the in-between mixes of the two flavors before fully switching being sold as undyed "White Surprise"s?
White Surprise fronting/blurring is when one headmate is switching out and another's switching in, but theyre blurring together the entire time, until the new front fully takes the front and the old front leaves.