Nextjs 15.1 not saving Static Content on Redis on build time using instrumentation using @neshca/cache-handler

[joanaavelar]

Link to the code that reproduces this issue

https://codesandbox.io/p/devbox/priceless-hill-52c3m3

To Reproduce

1. Update url from cache-handler with your Redis instance
2. yarn install
3. yarn build
4. Verify that no key exists for /index in Redis
5. yarn start
6. Verify that no key exists for /index in Redis, but /xpto in Redis exists
7. Go to the browser and open => http://localhost:3000/
8. Verify that /index key exists in Redis

Current vs. Expected behavior

I was expecting to have /index and /xpto after yarn build. I don't have anything being saved.
I was expecting to have /index also after yarn start. I only have /xpto being saved.

Provide environment information

Operating System:
  Platform: win32
  Arch: x64
  Version: Windows 10 Enterprise
  Available memory (MB): 32401
  Available CPU cores: 12
Binaries:
  Node: 22.4.1
  npm: 10.9.0
  Yarn: 1.22.22
  pnpm: N/A
Relevant Packages:
  next: 15.1.4 // Latest available version is detected (15.1.4).
  eslint-config-next: N/A
  react: 19.0.0
  react-dom: 19.0.0
  typescript: N/A
Next.js Config:
  output: standalone

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

Instrumentation

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

next build (local), next start (local)

Additional context

I was expecting to use instrumentation implementation and have Redis cache being populated with pre-rendered pages on build time, but it's only happening on start time. Besides that, I am unable to save the pre-rendered page if my page is on the root of the app, meaning app/page.tsx.
This issue happens both in 15.1 and 14.2.17 next versions.