Misinformation is usually anything of personal account or witness because experts and stories are what people used to believe as truth. But not many do any more.
And as always, the definition of "misinformation" - many times known as "information I don't like" - is left up to the authors.
In the paper, the authors address issues related to the definition of "misinformation".
As always, hallucinations seem to be as much in the realm of humans than AI, but even chatgpt wouldn’t have made up something like this because the definition is right in the article.