Issue Summary

When i access a SSG page that returns a redirect the JSON response is shown instead of the redirect made. The root cause of this is the PR #2393 from @KensukeTakahara i guess.

Pretty sure there just needs to be a if some where.

Actual behavior

When a SSG page returns a redirect and you access it directly it returns JSON instead of the actual redirect response. When access the .json version of the page it should be fine. Can't test this currently.

Expected behavior

When access directly it should return the redirect response directly.

Steps to reproduce

1. Return a redirect in getStaticProps
2. Access the page directly

Versions

It works on 3.7.0-alpha.10 every version above breaks it.