Your offline eval score has held steady at 88 for three months on a golden set built at launch. Over the same period, the user retry rate climbed from 8% to 14%. No model or prompt changes shipped. What is the most likely explanation, and what is the right response?

1. A Latency has regressed and users retry slow responses; answer quality is fine because the offline eval score has stayed flat.
2. B User inputs have drifted away from the golden set. Cluster recent queries, compare them to eval coverage, and add new cases.
3. C The provider silently changed model weights behind the endpoint; pin a model version and the retry rate will return to baseline.
4. D Retry rate is a noisy, lagging signal; wait for the offline score to move before acting, since it is the more reliable quality gate.