My favorite example is documented in Bully for Brontosaurus (see https://www.amazon.com/Bully-Brontosaurus-Reflections-Natura... if you want to buy it) in the essay, "The case of the creeping fox terrier clone." For close to a century, the first thing that everyone learned about the early horse Euohippus, officially known as Hyracotherium, was that it was "about the size of a small fox terrier". This despite the fact that essentially nobody knew what size a small fox terrier WAS. And despite the fact that later research found that the animal in question actually weighed several times what a fox terrier does! (But the shoulder height is indeed close.)

I've certainly seen the phrase "like the Nobel for mathematics" many times. I couldn't even have cited the original source. But it doesn't surprise me if this is the only thing most people have heard about the Fields medal. And it also doesn't surprise me that it would come from a movie.

Sure. Except that most people under the age of 25 probably haven't heard of the Fields medal anyway, unless it's from someone who watched GWH.

I don't think the suggestion was that everyone watched GWH and then had that misconception straight from primary source.

I probably view(ed) it a bit wrongly too, and I have seen GWH, but I'm pretty sure I'd read ('pop math'/news) about the award/it's winners before that.