LLM Model Degradation: A Postmortem of Degraded Performance Across Multiple Models
LLM model degradation is a slow, quiet loss of answer quality or speed that leaves every health check green: requests still return HTTP 200, error rates stay flat, and latency may not move at all. The 2025–2026 vendor postmortems show it is usually caused by infrastructure or configuration bugs — not by demand, time of day, or server load — and it is diagnosed by semantic monitoring, not uptime dashboards. ...