I did dual enrollment in 11th grade, but none of those courses are UC Transferable. I should report them in the "other coursework", but when I try to move on with the "College Courses taken in High School" section, I have to list at least one course

Colleges & Universities University of California - GENERAL
2

Why is it not transferable?

Any dual enrollment class must be reported under the college you received the dual credit through.