notFound function does not render not-found page and instead causes page crash (App Router, Next 16)

[CesarFont]

Link to the code that reproduces this issue

https://github.com/alexismendez11/ecommerce-demo

To Reproduce

1. Navigate to https://v0-ecommerce-next-js-app.vercel.app/menu
2. Go to a non existent category page (ex. https://v0-ecommerce-next-js-app.vercel.app/menu/category/test)
3. You will see the page crash with the message

Current vs. Expected behavior

current: the site crashed. and you will see this message "Application Error"
expected: see the content of the defined NotFound page

Provide environment information

Next.js: 16.x (also reproducible on latest canary)
React: 19.x
Router: App Router
Node.js: 22.x
Package manager: pnpm
OS: macOS 
(also reproducible on other team machines)
Browser: Chrome 145.x
Architecture: Dynamic route (/menu/category/[slug])
Data layer: External CMS (Prismic), but issue appears framework-level

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

Error Handling, Use Cache, cacheComponents, Dynamic Routes

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

next build (local), next start (local), Vercel (Deployed)

Additional context

No response

[icyJoseph]

Hiyo, I am able to reproduce this issue. I'll do a quick triage round.

[icyJoseph]

I've like found a few things, let me get my thoughts in order and try to reproduce in another way.

[laurenhall1526-netizen]

Do update me later on this

…

On Wed, Mar 4, 2026, 12:15 AM Joseph ***@***.***> wrote: *icyJoseph* left a comment (vercel/next.js#90837) <#90837 (comment)> I've like found a few things, let me get my thoughts in order and try to reproduce in another way. — Reply to this email directly, view it on GitHub <#90837 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/B7IHA437UOM6KPSSDYQJBO34O5YQ3AVCNFSM6AAAAACWF5X4J6VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTSOJUGM3DMNBXGY> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[jimrandomh]

We also experienced this and worked around it by adding a wildcard route. We were only able to reproduce it in the Vercel deployment environment and not locally.

[icyJoseph]

Mmm there's a few ways to get lost on this issue, but the root cause is that the server sent 404, is handled incorrectly by the client handles, and eventually that leads to a client-side-exception. In contrast, a redirect is handled correctly.

Another way to fix this issue in OP's case would be to cache the category getter function in generateMetadata.

But that's a change in user land code behavior. The fix should be that the client handles the 404 correctly.

[mondyzzz-glitch]

感谢反馈！我们看到了你的issue请求。我们会尽快处理。

[sydneyvaughn75-ops]

Yes same happens to me sometimes

…

On Sat, Mar 7, 2026, 2:19 PM mondyzzz-glitch ***@***.***> wrote: *mondyzzz-glitch* left a comment (vercel/next.js#90837) <#90837 (comment)> 感谢反馈！我们看到了你的issue请求。我们会尽快处理。 — Reply to this email directly, view it on GitHub <#90837 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/B7HZNKZMFLCK74BS6AST3O34PQVX3AVCNFSM6AAAAACWF5X4J6VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHM2DAMJWGU4TMOJVGY> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[canyonopm3026-create]

Alright thank you for the workaround I will try it and update u later On Sat, Mar 7, 2026, 4:50 PM sydneyvaughn75-ops ***@***.***> wrote:

…

*sydneyvaughn75-ops* left a comment (vercel/next.js#90837) <#90837 (comment)> Yes same happens to me sometimes On Sat, Mar 7, 2026, 2:19 PM mondyzzz-glitch ***@***.***> wrote: > *mondyzzz-glitch* left a comment (vercel/next.js#90837) > <#90837 (comment)> > > 感谢反馈！我们看到了你的issue请求。我们会尽快处理。 > > — > Reply to this email directly, view it on GitHub > <#90837 (comment)>, > or unsubscribe > < https://github.com/notifications/unsubscribe-auth/B7HZNKZMFLCK74BS6AST3O34PQVX3AVCNFSM6AAAAACWF5X4J6VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHM2DAMJWGU4TMOJVGY> > . > You are receiving this because you are subscribed to this thread.Message > ID: ***@***.***> > — Reply to this email directly, view it on GitHub <#90837 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/B7HYGQ2PIXVMRGRNI64CBLD4PRHO5AVCNFSM6AAAAACWF5X4J6VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHM2DAMJWHEYTENBZGQ> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[jakepaul8922-dotcom]

I will test and give u guys feedback On Tue, Mar 10, 2026, 11:01 AM canyonopm3026-create < ***@***.***> wrote:

…

*canyonopm3026-create* left a comment (vercel/next.js#90837) <#90837 (comment)> Alright thank you for the workaround I will try it and update u later On Sat, Mar 7, 2026, 4:50 PM sydneyvaughn75-ops ***@***.***> wrote: > *sydneyvaughn75-ops* left a comment (vercel/next.js#90837) > <#90837 (comment)> > Yes same happens to me sometimes > > On Sat, Mar 7, 2026, 2:19 PM mondyzzz-glitch ***@***.***> > wrote: > > > *mondyzzz-glitch* left a comment (vercel/next.js#90837) > > < #90837 (comment)> > > > > > 感谢反馈！我们看到了你的issue请求。我们会尽快处理。 > > > > — > > Reply to this email directly, view it on GitHub > > < #90837 (comment)>, > > > or unsubscribe > > < > https://github.com/notifications/unsubscribe-auth/B7HZNKZMFLCK74BS6AST3O34PQVX3AVCNFSM6AAAAACWF5X4J6VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHM2DAMJWGU4TMOJVGY> > > > . > > You are receiving this because you are subscribed to this thread.Message > > ID: ***@***.***> > > > > — > Reply to this email directly, view it on GitHub > <#90837 (comment)>, > or unsubscribe > < https://github.com/notifications/unsubscribe-auth/B7HYGQ2PIXVMRGRNI64CBLD4PRHO5AVCNFSM6AAAAACWF5X4J6VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHM2DAMJWHEYTENBZGQ> > . > You are receiving this because you are subscribed to this thread.Message > ID: ***@***.***> > — Reply to this email directly, view it on GitHub <#90837 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/B7HWMGIHJMPPDZJT4NAUIY34P7YW3AVCNFSM6AAAAACWF5X4J6VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHM2DAMZQGU2DONBYG4> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>