Hello. I am experiencing a possible Vercel builder/runtime regression.

Project: teclas-jade-web

Framework: Next.js 16.2.10 with Turbopack

Region: iad1

Production is currently healthy on deployment dpl_AzMAa2ncNtY4K2QLsYfs2RBApJBw, based on commit d4fb339, built on 2026-07-11.

A fresh redeploy of the same commit d4fb339 on 2026-07-17 produced a different build signature:

• nodejs lambdas changed from 3 to 5;
• • "Applying modifyConfig from Vercel" was absent;
  • • "Running onBuildComplete from Vercel" was absent.
  • A deployment from commit 8f2ac13 on the same date showed the same build pattern and failed at runtime:
• Vercel Runtime Error: failed to load env vars: EnvFileReadError(Os { code: 2, kind: NotFound, message: "No such file or directory" })

Affected deployment: dpl_35dxdhAZjqGaHhxfPRHwcoFXZRJH

The error came from edge-middleware and returned HTTP 500. The middleware source is identical between d4fb339 and 8f2ac13. No application code reads .env files at runtime, and production remains stable on the older deployment.

Could you investigate whether this is a regression in the Vercel Next.js builder or Edge Middleware runtime, and advise the recommended workaround?