I've had a few online code assessments that appear to have been hardened against ChatGPT "attacks". I failed at solving a problem that was just "Compute values of the Collatz conjecture for input n" because they wrote it to sound like an extremely difficult graph problem about being lost in a forest but being able to enter a "magic door".

I fed the problem into ChatGPT later and it was utterly unable to comprehend it, but confidently gave wrong answer after wrong answer.