sandbox NextJS build goes for 20min+

What version of the Codex App are you using (From “About Codex” dialog)?

26.303.1606 (806)

What subscription do you have?

$200

What platform is your computer?

Darwin 25.1.0 arm64 arm

What issue are you seeing?

When codex tries to make a build "next build" that normally takes <20s it gets stale. I am using a turborepo with 3 NextJS applications and it happens for all of them.
It happens ONLY in the sandbox environment (when codex did not ask me (i am using standard permissions))

<img width="763" height="263" alt="Image" src="https://github.com/user-attachments/assets/18527f1b-1368-406a-8e4d-29e1f6bda952" />

Would be fixable with a e.g. standard timeout or possibility to skip that without stopping the agent.

Normal output would be (gets stale after 2nd line):

[...]
▲ Next.js 16.1.6 (Turbopack)

[MDX] generated files in 19.385582999999997ms
  Creating an optimized production build ...
✓ Compiled successfully in 7.1s
✓ Finished TypeScript in 1730.7ms    
✓ Collecting page data using 13 workers in 335.4ms    
[...]

What steps can reproduce the bug?

• Setup Turborepo (might not be necessary but is my case and have not tested otherwise)
• 1. let it run a task where it needs to build a NextJS App "next build" in a sandbox (See it failing here)
• 2. Tell codex explicitly that he should ask about building outside of sandbox (See it succeeding here)

What is the expected behavior?

Building NextJS in under 20s.

Additional information

_No response_