I don't think there's translation error, the definition of fetish that used here is a usually handcrafted object (such as a carving) of spiritual significance that is believed to have the power to protect or aid its owner

Bc I read the Indonesian version of this book and that dialog was translated to "Azimat terkutuk harus dibuat dengan cantik." (Azimat means exactly what fetish is). I hope my explanation make sense ^^