The cookie set Secure from r.TLS, which is nil whenever TLS terminates at Traefik or Cloudflare, so a public deployment's session cookie went out without Secure. auth.IsHTTPS now decides it from X-Forwarded-Proto, believed only through the trusted-hop count (rule 94) and read positionally like X-Forwarded-For. Plain-HTTP and LAN logins are unchanged; nothing redirects. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>