I had Turn It In mark my work as plagiarism some years ago and I had to fight for it. It was clear the teacher wasn’t doing their job and blindly following the tool.
What happened is that I did a Q&A worksheet but in each section of my report I reiterated the question in italics before answering it.
The reiterated questions of course came up as 100% plagiarism because they were just copied from the worksheet.
This matches my experience pretty well. My high school was using it 15 years ago and it was a spotty, inconsistent morass even back then. Our papers were turned in over the course of the semester, and late into the year you’d get flagged for “plagiarizing” your own earlier paper.
What happened is that I did a Q&A worksheet but in each section of my report I reiterated the question in italics before answering it.
The reiterated questions of course came up as 100% plagiarism because they were just copied from the worksheet.