This has happened at my company. We give a similarly near-trivial hw problem, and sometimes people come in and literally "cannot remember" any single thing about the assignment, including the names of the columns in the data or the approximate objective of the HW. This is after performing plausibly well on a phone screen etc.

Thanks for clarifying this. This is what I meant when I said "Why would you want a job you are not qualified to do."

I am not so good with words sometimes... Haha...