Stale Worker Process Silently Wrote to Old Database After Config Update

A software developer reproduced a subtle bug where a background worker process continued using an outdated database URL even after the configuration was updated. The issue arose because the worker had been started before the deployment change, meaning it retained its original environment variables rather than picking up the new ones. Meanwhile, the API launched fresh with the correct settings, creating a split where two parts of the same system pointed to different databases. No errors or non-zero exit codes surfaced, making the bug invisible to standard monitoring and code review. The case highlights that deploying a correct config change is not enough if long-running processes are not restarted to inherit the updated environment.