Phrasing is not authorship
Detectors that claim to identify AI text are answering a provenance question with a style measurement, and the mismatch is why they disagree with each other and with reality.
Phrasing analysis avoids that error by not making the claim. It reports specific, countable properties of the prose, and lets an editor decide what they mean for this publication and this audience.
That distinction matters legally as well. A style score is a reasonable editorial input; it is a poor basis for accusing a writer.