What made the r/MachineLearning post this week unusual is not that an agent failed — it is how the failure presented . No exception was thrown. No evaluation turned red. The monitoring stack did its job correctly: it recorded every trace, logged every call, and reported a system in nominal operation. The problem was that the system was not in nominal operation. It had shifted into a state where it refused requests without announcing that refusal as an error. Support tickets were the only instrument that eventually detected it, and…