Fastlane android building: index.android.bundle missing

I am building an app bundle (.aab) for our react native app.

When I build via Android Studio, app builds, deploys to Play Store. I download and run - everything works.

When I build via FastLane, app builds, deploys to Play Store. But I download and run, I get the following error:

E AndroidRuntime: java.lang.RuntimeException: Unable to load script. Make sure you're either running a Metro server (run 'react-native start') or that your bundle 'index.android.bundle' is packaged correctly for release.
E AndroidRuntime:   at com.facebook.react.bridge.CatalystInstanceImpl.jniLoadScriptFromAssets(Native Method)
E AndroidRuntime:   at com.facebook.react.bridge.CatalystInstanceImpl.loadScriptFromAssets(CatalystInstanceImpl.java:2)
E AndroidRuntime:   at com.facebook.react.bridge.JSBundleLoader$1.loadScript(JSBundleLoader.java:1)
E AndroidRuntime:   at com.facebook.react.bridge.CatalystInstanceImpl.runJSBundle(CatalystInstanceImpl.java:3)
W ActivityTaskManager:   Force finishing activity com.friday.pax.dev/com.friday.pax.MainActivity

RN: 0.63.4
Gradle: 4.1.1

FastLane Logs:

https://gist.githubusercontent.com/HardlyMirage/4426e411b6ec1e8abac5e7a620d979ae/raw/37daead0b55ee77b7ef7d6ddd8631d311dbc80aa/txt

index.android.bundle appears to be correctly generated.

> Task :app:bundleDevReleaseJsAndAssets
warning: the transform cache was reset.
Welcome to React Native!
Learn once, write anywhere
info Writing bundle output to:, /home/runner/work/fridayapp-pax/fridayapp-pax/android/app/build/generated/assets/react/dev/release/index.android.bundle
info Writing sourcemap output to:, /home/runner/work/fridayapp-pax/fridayapp-pax/android/app/build/generated/sourcemaps/react/dev/release/index.android.bundle.map
info Done writing bundle output
info Done writing sourcemap output
info Copying 88 asset files
info Done copying assets

Task :app:mergeDevReleaseResources is run after Task :app:copyDevReleaseBundledJs

FastFile:

def getVersionCode
  # Instead of managing the version code manually it is simply based on a timestamp in sec
  # Any build done more recently is considered to be a higher version
  # versionCode increase every minute (aka max 1 build per minute)
  # versionCode can't be smaller than legacyVersionCode
  thirtySeptemberTwentyTwenty = 1601480940 / 60
  legacyVersionCode = 10902
  versionCode = legacyVersionCode + (Time.now.to_i / 60) - thirtySeptemberTwentyTwenty

  if versionCode > 2100000000
    raise "versionCode cannot be higher than 2100000000"
  end

  versionCode.floor()
end

platform :android do

  desc "Friday (Dev)"
  lane :playstoreDevInternal do |options|
    
    # Retrieve version of my app in package.json (React Native case)
    package = load_json(json_path: "../package.json")

    # Clean build folder
    gradle(
      task: "clean"
    )

    # Bump android.defaultConfig.versionCode
    # bump_build_number
    android_set_version_code(
      version_code: package["versionName"]
    )

    # Do the bundle of the application  
    gradle(
      # task: "assemble",
      task: 'bundle',
      flavor: "dev",
      build_type: "Release",
      properties: {
        "android.injected.signing.store.file" => Dir.pwd + "/release.keystore",
        "android.injected.signing.store.password" => options[:RELEASE_KEYSTORE_PASSWORD], # keystore password
        "android.injected.signing.key.alias" => options[:RELEASE_KEYSTORE_ALIAS], # alias
        "android.injected.signing.key.password" => options[:RELEASE_KEYSTORE_KEY_PASSWORD], # key password
        "vname" => package["version"]
      }
    )

    # Upload Android App Bundle to PlayStore like Internal testing Release
    upload_to_play_store(
      package_name: 'com.friday.pax.dev',
      track: 'internal',
      release_status: 'draft',
      skip_upload_apk: true,
      version_name: package["version"]
    )
  end
end

Can anyone point out why the aab bundle from Android Studio works, but not the one generated via FastLane? Even though index.android.bundle is clearly generated.

My only thought is that perhaps the index.android.bundle path is incorrect. But I don't see a way of modifying that path.

from Fastlane android building: index.android.bundle missing