Monorepo build failing after version 15.0.3 onwards

[digoburigo]

Link to the code that reproduces this issue

https://github.com/t3-oss/create-t3-turbo

To Reproduce

1. Clone repo and install the deps with pnpm
2. Update to version 15.0.2, build it and it works
   OBS: change the root package.json to include the build command to only build nextjs
   "build:next": "CI=true turbo run build -F @acme/nextjs...",
3. Update to version 15.0.3 or 15.0.4, build it again and you will see that the external packages are not found and the build fails, for example:

@acme/nextjs:build:    Creating an optimized production build ...
@acme/nextjs:build: Failed to compile.
@acme/nextjs:build:
@acme/nextjs:build: ./src/app/layout.tsx
@acme/nextjs:build: Module not found: Can't resolve '@acme/ui/theme'
@acme/nextjs:build:
@acme/nextjs:build: https://nextjs.org/docs/messages/module-not-found
@acme/nextjs:build:
@acme/nextjs:build: ./src/app/layout.tsx
@acme/nextjs:build: Module not found: Can't resolve '@acme/ui/toast'
@acme/nextjs:build:
@acme/nextjs:build: https://nextjs.org/docs/messages/module-not-found

Current vs. Expected behavior

I expected to build it normally like in the 15.0.2 version

Provide environment information

Operating System:
  Platform: darwin
  Arch: arm64
  Version: Darwin Kernel Version 24.1.0: Thu Oct 10 21:03:15 PDT 2024; root:xnu-11215.41.3~2/RELEASE_ARM64_T6000
  Available memory (MB): 16384
  Available CPU cores: 8
Binaries:
  Node: 22.12.0
  npm: 10.9.2
  Yarn: N/A
  pnpm: 9.14.4
Relevant Packages:
  next: 15.0.4 // Latest available version is detected (15.0.4).
  eslint-config-next: N/A
  react: 18.3.1
  react-dom: 18.3.1
  typescript: 5.6.3
Next.js Config:
  output: N/A

Which area(s) are affected? (Select all that apply)

Module Resolution, Output (export/standalone), Webpack

Which stage(s) are affected? (Select all that apply)

next build (local)

Additional context

No response

[mischnic]

(This is not a Turbopack but a Webpack build, you're just using Turbo as a task runner)

This is effectively a duplicate of #71001, just for Webpack instead of Turbopack