We saw something very similar. What made it clear wasn’t a sudden drop in accuracy, but the growing gap between what the model said and what teams were experiencing on the ground. People started questioning individual predictions, adding guardrails, or bypassing the model altogether in specific scenarios. That behavior shift was the real signal that something had changed.
Once we investigated beyond aggregate metrics, the issue became obvious. Feature distributions had drifted, and certain edge cases were now showing up far more often than they did during training. Looking at segment-level performance and input data health helped us validate the impact early and make targeted fixes before the problem showed up as a major business failure.
