Maybe your batch got too much melamine. It is just supposed to increase the protein level enough to trick the assaying company, but not so much to damage your liver fatally.
Something has to be added to make up for however the added protein was put in! And it's rarely the tasty salt, fat, acid, or sugar because those are the opposite of what health reading people want
So we get low flavor high texture ingredients instead
"Added protein" = "we poured in a load of surplus dairy byproducts". Protein tastes good if it triggers the umami receptors, which I don't think whey proteins do unless you age them (i.e. make mature cheese)
I think might just come down to marketing:
Granola bar with added peanuts: the peanuts taste good, so we’ll market it as high-protein
Lettuce with added milk powder: this tastes bad, so we’ll market it as added-protein or else no one will want to buy it
