I've heard the same thing levelled at artificial banana flavor (that it doesn't taste right because it is made to resemble Gros Michel strains of banana, which was decimated by fungus in the 1950s and we now mostly consume Cavendish bananas). I'm not sure I buy that one 100% -- sure isoamyl acetate exists at higher concentration in Gros Michel bananas, but a side issue is that some of the flavor profile of bananas comes from molecules with aldol-reaction formed bonds, which can be finicky under different pHs and may not be reasonable to include in some candy-making processes. Same may be true for artificial grape and it not tasting like table or wine grapes.