Long story short, I took an online class for an honors math class i got a really bad grade on but the reason I took it online over the summer (during my 11th grade year) was b/c my school did not have a summer class for that honors class. Onto the question, the grade is reflected on my transcript for my “real high school” just fine however it does say out of district. That being said, Should I add another secondary school b/c adding another is implying that I “quit the above secondary school” according to the common app. Anyhow, cheers and happy new years!
When you add a secondary school (and this is based on my experience, which is similar to yours), there’s a box where you can explain the reason you attended it outside your main high school. I’d say you could simply explain as you did above why there were multiple schools you attended, and that would be fine.