[regression] `app/not-found.tsx` throws FUNCTION_INVOCATION_FAILED server error instead of rendering the custom error page when cacheComponents are enabled

[Grod56]

Link to the code that reproduces this issue

https://codesandbox.io/p/devbox/9smrdm

To Reproduce

1. Run the application in production i.e. next start (error only occurs in production environments)
2. Navigate to an unmatched route that invokes notFound() in the base layout.tsx (e.g. /random.xml)
3. The application throws the above mentioned server error instead of serving the custom 404 page

Current vs. Expected behavior

The application works as intended with the same code and exact same steps when rerun in Next.js 16.2.3 suggesting a regression between that version and Next.js 16.2.6. Like I mentioned before, the issue only comes up in production environments with cacheComponents enabled and does not reproduce in dev builds.

Request Logs:

[Error: An error occurred in the Server Components render. The specific message is omitted in production builds to avoid leaking sensitive details. A digest property is included on this error instance which may provide additional details about the nature of the error.] {
  digest: 'NEXT_HTTP_ERROR_FALLBACK;404'
}
[Error: An error occurred in the Server Components render. The specific message is omitted in production builds to avoid leaking sensitive details. A digest property is included on this error instance which may provide additional details about the nature of the error.] {
  digest: 'NEXT_HTTP_ERROR_FALLBACK;404'
}
[Error: An error occurred in the Server Components render. The specific message is omitted in production builds to avoid leaking sensitive details. A digest property is included on this error instance which may provide additional details about the nature of the error.] {
  digest: 'NEXT_HTTP_ERROR_FALLBACK;404'
}
[Error: An error occurred in the Server Components render. The specific message is omitted in production builds to avoid leaking sensitive details. A digest property is included on this error instance which may provide additional details about the nature of the error.] {
  digest: 'NEXT_HTTP_ERROR_FALLBACK;404'
}

Provide environment information

Operating System:
Platform: win32                                                                                                         
Arch: x64                                                                                                               
Version: Windows 10 Enterprise                                                                                          
Available memory (MB): 4009                                                                                            
Available CPU cores: 4                                                                                                
Binaries:                                                                                                                 
Node: 22.16.0                                                                                                           
npm: 11.12.1                                                                                                           
Yarn: N/A                                                                                                               
pnpm: 9.15.4                                                                                                          
Relevant Packages:                                                                                                        
next: 16.2.6
eslint-config-next: N/A                                                                                                 
react: 19.2.4                                                                                                           
react-dom: 19.2.4                                                                                                       
typescript: 5.9.3                                                                                                     
Next.js Config:                                                                                                           
output: N/A

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

Error Handling

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

next start (local)

Additional context

No response

[Tanixq]

I’m investigating this regression and trying to reproduce it locally. I’ll share findings or a potential fix if I can identify the root cause.

[Grod56]

I’m investigating this regression and trying to reproduce it locally. I’ll share findings or a potential fix if I can identify the root cause.

Will try to have a sandbox up in a few minutes for a more minimal and focused reproduction

[Grod56]

I’m investigating this regression and trying to reproduce it locally. I’ll share findings or a potential fix if I can identify the root cause.

UPDATE: I've added a codesandbox that reproduces the issue, and I've updated the original post with a few more salient details.

[Tanixq]

I was able to reproduce the regression in the minimal sandbox reproduction.

I confirmed the issue only occurs in production mode (next build && next start) when cacheComponents is enabled.

With cacheComponents: true, visiting /random.xml results in a 500 response and repeated NEXT_HTTP_ERROR_FALLBACK;404 errors during the Server Components render.

After disabling cacheComponents, the same route correctly renders the custom 404 page instead of failing.

[waldosmuts]

Getting the same behavior in production on next@16.2.6 with cacheComponents: true.

In my case, it only happens when notFound() is triggered.

Navigating to a non-existent route still renders the root not-found.tsx as expected.