You ever devour a Butterfinger and spend the next ten minutes picking bits off your molars? I have. It’s a feature, not a bug. The combination of corn syrup and sugar creates a glass-like structure when it cools. It’s hard, brittle, and eager to adhere to enamel.
Think of it as a temporary filling. You paid for candy, but you get a minor dental adventure. It’s the candy bar that says, “You’re not leaving until every bit of me is gone.”