Next.js 16 — Streaming Soft-404s and ISR Blockers
Verified: 2026-06-11. Two related Next.js 16 App Router production failures, found and fixed across PewSearch, ITW, and churchwiseai-web on 2026-06-09/10. Both are invisible in dev and in "build passes" checks — they only show in HTTP status codes and the prerender manifest.