Omg I figured out I’m not crazy. So, I’ve always believed that things like M&Ms have different flavors, but I disbanded that theory as I grew up. HOWEVER, the Rainbow goldfish are an exception.
Everyone keeps arguing that they taste exactly the same and I kept saying, “It probably has something to do with the dye.” And everyone says that food dye has no flavor... and while that is correct, goldfish uses natural dyes which DO have flavor. So, they unintentionally made the rainbow goldfish taste different and I’ve been right about it all along :)