[i18n] multiple locales in path

[AntoineBourin]

What version of Next.js are you using?

10.1.1

What version of Node.js are you using?

12.0.0

What browser are you using?

Chrome, Firefox

What operating system are you using?

macOS

How are you deploying your application?

next dev

Describe the Bug

I have a website with next i18n enabled on it.
The configuration of i18n translation is described like this :
i18n: { locales: ['fr-fr', 'fr-be', 'nl-be'], defaultLocale: 'fr-fr', },

Translation working as expected but we have a problem when multiple locales are defined in path.

For example, with i18n translation with the following configuration, we expected 404 error page to be triggered :
localhost:3000/fr-fr/fr-be
localhost:3000/fr-fr/nl-be
localhost:3000/fr-be/nl-be etc...

Expected Behavior

For these pages described above, the index page is triggered and the last locale wrote in path is selected.
localhost:3000/fr-fr/fr-be => display index instead of 404 page => select fr-be locale in context
localhost:3000/fr-be/nl-be => display index instead of 404 page => select nl-be locale in context

To Reproduce

Just create a nextJS project, add next-i18n and add some locales in the configuration file.
Create a simple index.js page in pages directory.

Try to access to your website with multiple locales in path. Instead of displaying 404 error page, your index page will be show.

[ijjk]

Closing as a duplicate of #20120

[balazsorban44]

This issue has been automatically locked due to no recent activity. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.