This is real. Years ago I was studying for a professional accountancy exam. In the industry magazine there was an article about a specific subject written by the chief examiner. I go to a revision course where the guy taking it says this WILL come up in the exam. So we spend a weekend going over this subject until we know it backwards. Come the exam, I’m feeling confident. Open the paper, not one exam question covered that area. Mind blown. I did complete the paper, but with my mind all over the place and left about 30 minutes early. I failed the paper by less than 5 marks. Absolutely gutted. Had to retake, and did pass.
Reminds me of an episode of the Tick... He hallucinated in Mexico, found a talking dog and brought it home. Turned out to be a capybera. Among the best episodes of the series.
My high school had a one semester class that tried to cover this stuff. It was a good idea, but the teacher that led the class was a very annoying uptight man.