Facebook sign-ins fail with "Unable to process request due to missing initial state" on Android Chrome

### Operating System

Android 16

### Environment (if applicable)

Chrome 140

### Firebase SDK Version

12.2.1

### Firebase SDK Product(s)

Auth

### Project Tooling

Aurelia v1

### Detailed Problem Description

We have an increasing number of users on Chrome Android seeing the `Unable to process request due to missing initial state...` response after they go through the login flow for Facebook and are redirected back to the auth handler. I'm able to reproduce it on my Pixel 6a, but it is also happening on Samsung devices.

### Steps and code to reproduce issue

We're following best practices option 3 so there's no cross-domain data or 302 Redirects, it all passes through the proxy transparently.

On Chrome Android, `signInWithRedirect` and `signInWithPopup` produce the same issue.

On Firefox Android, `signInWithRedirect` works while `signInWithPopup` fails.

There are no other auth errors until the auth handler tab is closed, then the `user-cancelled` or `popup-closed-by-user` error comes through.