I asked ChatGPT who I was not too long ago. I have a unique name and I have many sources on the internet with my name on it (I'm not famous, but I've done a lot of stuff) and it made up a multi-paragraph biography of me that was entirely false.
I would sure as hell call that a hallucination because there is no question it was trained on my name if it was trained on the internet in general but it got it entirely wrong.
Curiously, now it says it doesn't recognize my name at all.