It is particularly bad when trying to find the reality behind common misconceptions.

Even when there is no evidence to support something, and no motivation for anyone to promote the falsehood, models can build an ediface out of false claims.

There are always people prepared to invent a story to explain why something is true. Just so they can sound knowledgeable. They aren't trying to perpetuate a lie, they are just under the same misconception as others, quite a lot of them will believe their invented explanation even as they say it.

It's going to be a difficult task making an AI pick the correct one of two mutually exclusive pieces of evidence, especially after it has found one piece and does not yet know the other exists.