Why do Sonic's Cheddar Peppers taste weird, like a chemical or something is in them?

I love their cheddar poppers, but the last few times I've had them, they have tasted tainted. Some of them taste like a chemical or something is in them. Sometimes it's 2 of the 4 that are bad, sometimes all of them. It's not always been that way, just the last month or so. Anybody else noticed this?