Fishprof, Elsie's described it well-
Dual enrollment is handled differently at different places. Some colleges have the students come to the campus and take classes with regular students. Some colleges send their instructors to the high schools to teach the students within the course of their high school day. Still others hire high school teachers with master's degrees, who are also teaching regular high school courses, to teach these courses, even as they also cover what's required by state expectations for high school courses. Thus, dual enrollment composition courses at the latter schools are just as much 12th grade English, if not more so, as they are college composition courses.
Many a teacher just keeps on teaching 12th grade English with barely a nod to the requirements of the college course he or she is supposedly teaching. We've seen students who supposedly have credit for the research composition course who wrote at best a three page "research" paper with a few sources from the internet. My colleague's daughter had just such a DE course, and her mother made sure that daughter retook the comp courses when she enrolled at the community college. But then we also get students who had a real college level course for their DE credit. It's so variable.
Elsie's second paragraph is where we are having problems and if these issues are not addressed, I think there's going to be a big stink when it comes to accreditation.
Alan