nextjs repro - basePath + middleware + pages routes = full roundtrip

Hello.

Here is a repro about an issue we are experiencing with pages router. Conditions are the following:

• Using a basePath.
• Using middleware.
• Using pages router.
• Index page using getServerSideProps.

Symptoms

• Client navigation from / -> /yolo = OK.
• Client navigation from /yolo -> / = Full roundtrip. We appear to have a 404 on getting index.json, as shown in the recording, even though the file exists.