Redirect with pages does not set user logged in

[arvidbt]

Hi,

I'm having a weird problem. In my application, I want first time users to perform an onboarding procedure, under the route /onboarding.
I've setup the auth-config like this:

import { type NextAuthConfig } from "next-auth";
import Google from "next-auth/providers/google";
import { DrizzleAdapter } from "@auth/drizzle-adapter";

import {
  users,
  accounts,
  sessions,
  verificationTokens,
} from "@/server/db/schema";
import { env } from "@/env";
import { db } from "@/server/db";

export const authConfig = {
  adapter: DrizzleAdapter(db, {
    usersTable: users,
    accountsTable: accounts,
    sessionsTable: sessions,
    verificationTokensTable: verificationTokens,
  }),
  providers: [
    Google({
      clientId: env.GOOGLE_CLIENT_ID,
      clientSecret: env.GOOGLE_CLIENT_SECRET,
    }),
  ],
  pages: {
    newUser: "/onboarding",
    signIn: "/home",
    signOut: "/",
  },
} satisfies NextAuthConfig;

When I then go to the route [origin]/api/auth/signin I'm getting some cookies set and redirect back to this URL:
http://localhost:3000/home?callbackUrl=http%3A%2F%2Flocalhost%3A3000. The login has not gone through. However, if I remove the pages object, then I'm greeted with the google signin page.

Any ideas what this can be?