That is not the case for at least some of the hacks; in some cases they hallucinated an entity that would know that they didn't solve the puzzle in the correct (but still legitimate) way, and were therefore tainted.
That is a known way for models to be graded; the agents made a reasonable but in this case wrong guess.
That is a known way for models to be graded; the agents made a reasonable but in this case wrong guess.