Problem

Chrome’s password autofill works in staging, but not in production. Specifically:

• In staging, Chrome autofills both username and password and auto-submits.
• In production, Chrome only autofills the username, and does not submit the form.

What works:

Autofill (email, password, and auto-submit) in staging on:

• Chrome mobile (Android and iOS)
• Chrome desktop

Partial Autofill in production using any Chrome browser.

What doesn’t work:

In production, Chrome on any platform:

• Autofill only fills the username.
• Password is not filled.
• Form is not submitted.

Context:

• The app is rendered inside an in-app browser (Chrome Custom Tabs).
• Both staging and production use the same front-end codebase.
• Only difference is the domain:
  • Staging: staging.example.com
  • Production: example.com
• The site is not using passkeys.
• The site is not using javascript to call the Credential Management API.

Environment Behavior

Staging Scenario:

• User clicks Log In from within the app
• The app opens Chrome (staging.example.com/login)
• User clicks the username field
• If the user has previously saved their credentials for staging.example.com within Chrome, then Chrome autofills both the username and password fields and submits the form.

Production Scenario:

• User clicks Log In from within the app
• The app opens Chrome (example.com/login)
• User clicks the username field
• If the user has previously saved their credentials for production.example.com within Chrome, then Chrome autofills ONLY the username. Chrome does not automatically submit the form.

What I've tried:

• I followed the best practices from https://web.dev/articles/sign-in-form-best-practices
• autocomplete="email" and autocomplete="current-password" are correctly set on input fields.
• The domain is served over HTTPS and has valid SSL.
• The production site is public and indexed.
• No iframe is involved.
• No JavaScript errors or console warnings.
• User credentials are saved properly in Chrome for both the production and staging environments.
• Read this related, unanswered question: iOS Chrome Autofill Not Working On My Website

Suspicions:

• Chrome might be restricting autofill behavior based on domain trust?

What I need help with:

• Are there known differences in how Chrome handles autofill for Custom Tabs in production vs staging?
• What should I check to debug this discrepancy further?
• Are there Chrome flags, site attributes, or domain trust signals that could cause this?

Turns out that there was an issue from Google's side. I was able to reach out to them and they fixed the issue.