I've been hearing "it's not just... it's a" touted as an AI sign recently, personally I think it's an AI sign because it's a human thinking shortcut sign, and AI copies it, but it would be funny if AI wrote the article and then hallucinated this specific money quote.
I doubt this happened here, but FWIW, AI does have a habit of "cleaning up" (read: hallucinating) interview transcript quotes if you ask it to go through a transcript and pull quotes. You have to prompt AI very specifically to get it to not "clean up" the quotes when you ask it to do that task.
And why not?
If you look at examples of people quoting on the internet, lots are out of context, paraphrased, or made up.
AI is just mimicking what it has seen.