I grew up with dumdums and tootsie rolls doing this because of how the machines made batches of different flavors. The mystery flavors were just mysteries because during the change between flavor productions, there’s a margin of error so they just wrapped the candy made in between two flavors as “mystery flavors” since they couldn’t be 100% sure what flavor it was gonna have anyway.

I don’t think that’s what Mountain Dew is doing though. They totally know what flavor it is, they just don’t wanna tell you it’s dog vomit and hairball.