Real root cause of the 2026-06-01 full-site 502 was not a missed
reference but an out-of-band fix that Terraform reverted: the 2026-05-30
Traefik .200->.203 migration repointed the Cloudflare tunnel to the
Traefik service DNS via the CF Global API Key, but never landed that
change in cloudflare.tf (left at .200). A terragrunt apply on 2026-06-01
reconciled live back to the stale .200, breaking all external ingress.
Rewrite the post-mortem around the "codify out-of-band fixes or TF
reverts them" lesson (a Terraform-Only-rule violation).
Also fix docs/runbooks/kms-public-exposure.md, which still claimed
Traefik served on 10.0.20.200:443 (now .203) — same migration fallout.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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