Mentor Say there is an error in Scala two fer

When Two Fer failed with code that had passed locally, and again when I found an answer on the Internet, and cheated. I checked with a mentor, who said the code was correct, there was a bug in exercism.org's checking the code.

object Twofer {
def twofer(name: String = "you"): String = s"One for ${name}, one for me.";
}