Project Context:
I'm implementing a custom Vercel builder (esm with type:module) for Quasar Framework whit SSR mode.

Current Behavior:
While vercel dev works correctly during local testing, executing vercel deploy produces the following ES module error:

1Error: Importing "vercel-quasar": require() of ES Module 2/vercel/path1/.vercel/builders/node_modules/vercel-quasar/dist/index.js 3from /var/task/node_modules/vercel/dist/index.js not supported.45Instead change the require of /vercel/path1/.vercel/builders/node_modules/vercel-quasar/dist/index.js 6in /var/task/node_modules/vercel/dist/index.js to a dynamic import() 7which is available in all CommonJS modules.

Key Question:
Why does the deployment environment behave differently from the development environment regarding module resolution?

Reproduction Steps:

1git clone https://github.com/dongwa/quasar-ssr-vercel-demo2cd quasar-ssr-vercel-demo3pnpm install4vercel dev  # Works as expected5vercel deploy  # Produces the error

Related Repositories:

• Custom Builder: https://github.com/dongwa/vercel-quasar
• Test Project: https://github.com/dongwa/quasar-ssr-vercel-demo

Additional Details:

• Node.js version: v22.14.0
• vercel version:41.4.1

Would appreciate any insights into resolving this module compatibility issue between development and production environments.