I used gemini to look up a relative with a connection to a famous event. The relative himself is obscure, but I have some of his writings and I've heard his story from other relatives. Gemini fabricated a completely false narrative about my relative that was much more exciting than what actually happened. I spent a bunch of time looking at the sources that Gemini supplied trying to verify things and although the sources were real, the story Gemini came up with was completely made up.
Yup. I've had Gemini create fake citations to papers. I've also had it hallucinate the contents of paywalled papers, so I know I can't trust anything it writes, though I am getting better at using it recursively to verify things.