The edge proxy strips strong ETags whenever an HTML-rewriting feature is on, so the shell's validator never reached browsers — mark it weak, which rides through untouched. Make the catch-all HTML no-cache header set-if-absent so apps that send their own caching policy stop getting a doubled Cache-Control. Claude-Session: https://claude.ai/code/session_01FryvSZ4bmGcpc7q13FNaCj