With Jabbernuts shuffled, the Windmill man will give you a check when he sees your ocarina. Malon in Lon Lon uses the same mechanic and she ignores you when you pull out ocarina. (skip child zelda on, open kak gate)
One of these should be changed to match the other I think. Based on trade item behavior, I would guess Malon is the one to be fixed since "reacting to items" conversations seem to be allowed.