npm run serveのエラー

環境はこう。

>node -v && vue -V && npm -v
v16.14.2
@vue/cli 5.0.4
8.5.0

エラーはこう。

> my-project@0.1.0 serve
> vue-cli-service serve

 INFO  Starting development server...
 ERROR  ValidationError: Progress Plugin Invalid Options

        options should NOT have additional properties
        options should NOT have additional properties
        options should NOT have additional properties
        options should pass "instanceof" keyword validation
        options should match exactly one schema in oneOf

ValidationError: Progress Plugin Invalid Options

options should NOT have additional properties
options should NOT have additional properties
options should NOT have additional properties
options should pass "instanceof" keyword validation
options should match exactly one schema in oneOf

    at validateOptions (C:\Users\user\Desktop\my-project\node_modules\webpack\node_modules\schema-utils\src\validateOptions.js:32:11)
    at new ProgressPlugin (C:\Users\user\Desktop\my-project\node_modules\webpack\lib\ProgressPlugin.js:62:3)
    at new Progress (C:\Users\user\Desktop\my-project\node_modules\progress-webpack-plugin\index.js:25:21)
    at new progressPlugin (C:\Users\user\Desktop\my-project\node_modules\progress-webpack-plugin\index.js:127:10)
    at C:\Users\user\Desktop\my-project\node_modules\webpack-chain\src\Plugin.js:14:18
    at Object.toConfig (C:\Users\user\Desktop\my-project\node_modules\webpack-chain\src\Plugin.js:78:22)
    at C:\Users\user\Desktop\my-project\node_modules\webpack-chain\src\Config.js:129:63
    at Array.map (<anonymous>)
    at module.exports.toConfig (C:\Users\user\Desktop\my-project\node_modules\webpack-chain\src\Config.js:129:40)
    at Service.resolveWebpackConfig (C:\Users\user\Desktop\my-project\node_modules\@vue\cli-service\lib\Service.js:277:34)

結果、新しくvue create ….でプロジェクトを立てたらnpm run serveが通った。
いったい何だったんだ・・・。