Yes, that is indeed very unfortunate. Would definitely write in to CTY so that they can address. My D had attended the CTY 5-6 program at Stanford few years ago and had a very positive experience, and we were very impressed with the teacher and her assistant when we met for conference. D went to Lancaster this past summer and also loved that experience, including the instructor and fellow students. Sounded like her course (Prob & Game Theory) was quite rigorous enough.