Regarding UCSB’s admissions, they have been pretty upfront with the fact that they weigh extracurriculars and non academic factors heavily. We know a female engineering student with top scores who was denied. She had some (but not a lot) of activities outside of school. For engineering, they also chant “Math, Math, Math!” in that they want to see top grades in top math courses. They want to see top SAT/ACT math scores, top Math II subject test scores, etc.
It may be that the high GPA and high overall SAT/ACT students didn’t show top scores in enough math assessments or have enough extracurricular activities.