@EricR
1. Uniform rhythm and diction
This will also happen if the author is good at grammar and similar technical skills. I might be assessed like this.
2. Patterned description and sensory sequencing
This, by contrast, can indicate an author who writes too mechanically. That said, the mechanical construction could be something a human author was taught in school and adheres to slavishly.
3. Character and dialogue regularity
This still sounds like a symptom of an author who follows some rules too closely.
4. Derivative thematic blend
This happens in normal bad writing. At the same time, good authors have been known to take other stories and write better ones on the same theme. Some of Shakespeare's plays, for example.
5. Lack of deeper voice differentiation
I struggle to give my characters distinct personalities, too. I have noticed other stories where most of the characters are just mouthpieces for the author's voice, with the remainder being there to prompt them.
In summary, these seem like symptoms of a bad author with good technical skills, and I worry that it might also claim that my writing is AI-generated. (Of course, I've never written a story that got scored anywhere near 7.99, and I doubt anything I'm working on now will do much better than 6, so perhaps I should switch to AI :-P )