SSR and DSG pages include language twice inside matchPath

[denisgoryaynov]

I have some SSR routes that use getServerData to fetch some data, for example src/pages/products/[slug].tsx

These pages work correctly for the default language but for other language they contain the language twice, for example the component mentioned above becomes: /fr/fr/products/:slug

The expected behaviour would be for the page to be reachable at /fr/products/:slug, but it is not happening because this line of code duplicates the language:

gatsby-plugin-react-i18next/src/plugin/onCreatePage.ts

Line 109 in 2b7b55b

localePage.matchPath = `/${lng}${localePage.matchPath}`;

Removing the entire if condition fixes the issue.