UPDATE: READ HERE.
Well, after two washes I can safely say that they are in fact lovely high-quality sheets - on the crispy side so perfect for summer! It must have something to do with how they're made. What was an unexpected bonus was unlike how most bed sheets are packaged, they are packaged like a gift - no plastic, wrapped in tissue in an elegant box.
This is the blond me in my super-soft, gorgeous white sheets: