How Next.js Default Caching Silently Breaks Production Apps

This article reveals how Next.js's built-in data caching mechanism—designed for performance—can become catastrophic for applications serving real-time data like live sports scores. The bug exposes a critical gap between framework assumptions and production requirements, where stale cached data directly undermines core functionality. Understanding this pitfall is essential for developers building real-time features on the App Router, as the solution requires more than just adding cache configuration.