Amplify部署ReactNative(+Expo)成功但前端构建未执行，访问出现404

检查部署日志后发现，尽管构建设置指定要执行npx expo export:web，但前端构建阶段未运行任何操作，导致访问对应URL时出现404错误。

version: 1
applications:
    -
        backend:
            phases:
                build:
                    commands: ['nvm use 18', 'npm ci', 'npx amplify pipeline-deploy --branch $AWS_BRANCH --app-id $AWS_APP_ID']
        frontend:
            phases:
                build:
                    commands: []
            artifacts:
                baseDirectory: /
                files:
                    - '**/*'
            cache:
                paths: []
        appRoot: modules/app
frontend:
    phases:
        build:
            commands:
                - 'npx expo export:web'
    artifacts:
        baseDirectory: web-build

(...)
2023-12-06T22:32:50.466Z [INFO]:
2023-12-06T22:32:53.892Z [INFO]: # Completed phase: build
## Completed Backend Build
2023-12-06T22:32:53.895Z [INFO]: ## Starting Frontend Build
# Starting phase: build
# Completed phase: build
## Completed Frontend Build
2023-12-06T22:32:53.988Z [INFO]: ## Build completed successfully
2023-12-06T22:32:53.991Z [INFO]: # Starting caching...
2023-12-06T22:32:53.991Z [INFO]: Nothing to cache
2023-12-06T22:32:53.991Z [INFO]: # Caching completed
2023-12-06T22:32:53.993Z [INFO]: # No custom headers found.
2023-12-06T22:32:54.008Z [WARNING]: !! No index.html detected in deploy folder: /codebuild/output/src1323226312/src/appname/modules/app/
2023-12-06T22:32:54.008Z [INFO]: # Starting build artifact upload process...
2023-12-06T22:33:18.445Z [INFO]: # Uploading build artifact '__artifacts.zip'...
2023-12-06T22:33:18.454Z [INFO]: # Uploading build artifact '__artifactsHash.zip'...

内容的提问来源于stack exchange，提问作者hudsonmendes