useSession seems to reset post hydration

[nilskaspersson]

Hi,

I have an application with unknown dynamic pages that I protect using the new middleware withAuth. After acquiring a JWT and accessing the app, the following happens:

When Next.js is configured to use the "blocking" fallback method for the dynamic pages, useSession().status goes through loading to authenticated and remains persistent. All good.

However when I use fallback: true, the behavior changes; the immediate initialization goes through the same, but when useRouter().isFallback shifts from true to false, the session is seemingly flushed, goes through loading again, but results in unauthenticated—no request ever goes out to /api/auth/session for this second loading state. Forcing a revalidation through refetchOnWindowFocus immediately triggers a session request and sets the status to authenticated again.

I would hope for the behavior to be the same regardless of fallback mode.

I can't shake the feeling that I have misconfigured something, but I cannot find anything in the docs or example implementation that is strikingly different.

Am I going about something all wrong? Any insight is appreciated!