Disapointed With Brake Disc's

So I had some Pagid (iirc) disc's fitted approx. 3,000 miles ago but th other week they developed a brake judder, took them back to the garage that fitted them & was told they had a warranty so he would replace with a different make (that I can't recall) after 2 weeks they look like this







In the past I've only had OEM & they have never looked rusty like this, is this right?? :mad0259: