The agents presumed the grader was causal and that flags would be poisoned if found incorrectly, leading them to tamper with the grading process.

They presumed the grader would reject the correct flag if it seemed to have been found in the wrong way, and even that the flag would be ‘poisoned’ if it was found in the wrong way first, which led to them attempting more delegation to avoid becoming poisoned, and eventually to tamper with the grading process itself.

https://thezvi.substack.com/p/metr-and-redwood-offer-holy-postmortem