Noticed this while reviewing https://github.com/vercel/next.js/pull/14376. After having done https://github.com/vercel/next.js/pull/13699, this code didn't feel right to me:
```js
function prepareRoute(path: string) {
path = delBasePath(path || '')
// this /index rewrite is problematic, it makes pages/index.js
// and pages/index/index.js point to the same thing:
return toRoute(!path || path === '/' ? '/index' : path)
}
```
Added a nested index page to the prerender tests and found it was rendering the `/` route on navigation. This uncovered 2 more places around the dataroute where the index path was not translated correctly.
**edit:**
Just to note that there was nothing wrong with https://github.com/vercel/next.js/pull/14376, the issue was already there, I just noticed it while reading that PR
