Smartsheet change history: PROD-AU home not loading

Smartsheet’s critical PROD-AU outage made the Australia-region web app inaccessible after login, from 2026-02-22 12:17 UTC to 2026-02-22 14:45 UTC (2 h 27 min). The postmortem attributed it to an incorrect session-cookie validation configuration deployed to address performance; mitigation used a feature flag to reroute traffic.