You said your adjudicator is Maureen Yuen and she is not Korean I think. However, she was a killer 3 years ago. I recalled that she was the adjudicator of one of the viola junior group and all kids were given under 80, therefore no placings were given for the group. At that time, she also gave high marks for some of the kids as my friend also for 91 from her 3 years ago.
The Korean adjudicator this year is Miss Ji Hyun Son.