An example I have of this is when I asked Claude to copy a some functionality from a front-end application to a back-end application. It got all of the function signatures right but then hallucinated the contents of the functions. Part of this functionality included a look up map for some values. The new version had entirely hallucinated keys and values, but the values sounded correct if you didn't compare with the original. A human would have literally copied the original lookup map.
There is no way this is true. People make fewer bugs with time and guidance, but no human makes zero bugs. Also, bugs are not planned; it's always easy to in hindsight say "A human would have literally copied the original lookup map," but every bug has some sort of mistake that is made that is off the status quo. That's why it's a bug.