Resources not skipped by auth middleware

[cmma0003]

Environment

  System:
    OS: macOS 15.6
    CPU: (12) arm64 Apple M4 Pro
    Memory: 702.38 MB / 24.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 22.19.0 - ~/n/bin/node
    npm: 10.9.3 - ~/n/bin/npm
  Browsers:
    Chrome: 140.0.7339.186
    Safari: 18.6
  npmPackages:
    next: 15.5.2 => 15.5.2 
    next-auth: 5.0.0-beta.29 => 5.0.0-beta.29 
    react: 19.1.0 => 19.1.0 

Reproduction URL

https://github.com/cmma0003/authentication

Describe the issue

When deploying to Vercel (I've tried also Netlify), looks like the middleware config.matcher that excludes resources files do not work. I have done everything exactly as described here, but still does not work.
middleware.ts

export { auth as middleware } from "@/lib/auth/auth";

export const config = {
    matcher: ['/((?!api/auth|_next/static|_next/image).*)'],
};

auth.ts file:

export const { handlers, signIn, signOut, auth } = NextAuth({
    providers: [
        Cognito({
            authorization: { params: { scope: "openid email profile" } },
            checks: ["pkce", "nonce"]
        }),
    ],
    pages: {
        signIn: "/signin",
    },
    callbacks: {
        authorized: async ({ auth }) => {
            return !!auth?.user;
        },
        redirect: async ({ url, baseUrl })=> {
            if (url.startsWith("/")) return `${baseUrl}${url}`;
            if (new URL(url).origin === baseUrl) return url;
            return baseUrl;
        }
    },
});

It does work properly in my local environment, what is the reason behind this issue? TIA

How to reproduce

The url where it is deployed in Vercel here: https://authentication-lake-two.vercel.app/

Expected behavior

Resources are skipped from auth, no redirection happens for them to include as part of the callback

[cmorillo-nopan]

@JasperAlexander I've seen you replied to similar issue but in my case, I am using middleware config.matcher. Any other suggestion? TIA