Not able to load MDX in v6.5.8

[brendonco]

Not able to load MDX file in v6.5.8

To Reproduce

file.stories.mdx

import { Meta } from '@storybook/addon-docs/blocks';
import Changelog from './CHANGELOG.md';

<Meta title='Releases/CHANGELOG' />

<Changelog />

main.js

module.exports = {
  features: {
    storyStoreV7: true,
    babelModeV7: true,
    previewMdx2: true,
  },
  core: {
    builder: 'webpack5',
    disableTelemetry: true, // 👈 Disables telemetry
  },
  babel: async (options) => {
    options.plugins.push('babel-plugin-inline-react-svg');
    return options;
  },
  stories: ['../stories/**/*.stories.@(js|jsx|ts|tsx|mdx)'],
  addons: [
    '@storybook/addon-links',
    '@storybook/addon-actions',
    '@storybook/addon-viewport',
    {
      name: '@storybook/addon-docs',
      options: {
        configureJSX: true,
        babelOptions: {},
        sourceLoaderOptions: null,
        transcludeMarkdown: true,
      },
    },
    '@storybook/addon-controls',
    '@storybook/addon-backgrounds',
    '@storybook/addon-toolbars',
    '@storybook/addon-measure',
    '@storybook/addon-outline',
  ],
  framework: '@storybook/react',
};

System
Please paste the results of npx sb@next info here.

Environment Info:

  System:
    OS: Windows 10 10.0.19042
    CPU: (8) x64 11th Gen Intel(R) Core(TM) i5-1145G7 @ 2.60GHz
  Binaries:
    Node: 16.14.2 - ~\SoftwaresInstalled\node-v16.14.2-win-x64\node.EXE
    npm: 8.5.0 - ~\SoftwaresInstalled\node-v16.14.2-win-x64\npm.CMD
  Browsers:
    Chrome: 103.0.5060.114
    Edge: Spartan (44.19041.1266.0), Chromium (103.0.1264.49)
  npmPackages:
    @storybook/addon-actions: ^6.5.9 => 6.5.10
    @storybook/addon-backgrounds: ^6.5.12 => 6.5.12
    @storybook/addon-controls: ^6.5.12 => 6.5.12
    @storybook/addon-docs: ^6.5.10 => 6.5.10
    @storybook/addon-essentials: ^6.5.9 => 6.5.10
    @storybook/addon-links: ^6.5.9 => 6.5.10
    @storybook/addon-measure: ^6.5.12 => 6.5.12
    @storybook/addon-outline: ^6.5.12 => 6.5.12
    @storybook/addon-postcss: ^2.0.0 => 2.0.0
    @storybook/addon-storyshots: ^6.5.9 => 6.5.10
    @storybook/addon-storysource: ^6.5.9 => 6.5.10
    @storybook/addon-toolbars: ^6.5.12 => 6.5.12
    @storybook/addon-viewport: ^6.5.12 => 6.5.12
    @storybook/addons: ^6.5.9 => 6.5.10
    @storybook/builder-webpack5: ^6.5.9 => 6.5.10
    @storybook/manager-webpack5: ^6.5.9 => 6.5.10
    @storybook/react: ^6.5.9 => 6.5.10
    @storybook/react-docgen-typescript-plugin: ^1.0.1 => 1.0.1
    @storybook/theming: ^6.5.9 => 6.5.10

Error

ModuleBuildError: Module build failed (from ./node_modules/@storybook/mdx2-csf/loader.js):
TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".json" for \node_modules\character-entities-legacy\index.json
    at new NodeError (node:internal/errors:371:5)
    at Object.getFileProtocolModuleFormat [as file:] (node:internal/modules/esm/get_format:87:11)
    at defaultGetFormat (node:internal/modules/esm/get_format:102:38)
    at defaultLoad (node:internal/modules/esm/load:21:14)
    at ESMLoader.load (node:internal/modules/esm/loader:359:26)
    at ESMLoader.moduleProvider (node:internal/modules/esm/loader:280:58)
    at new ModuleJob (node:internal/modules/esm/module_job:66:26)
    at ESMLoader.#createModuleJob (node:internal/modules/esm/loader:297:17)
    at ESMLoader.getModuleJob (node:internal/modules/esm/loader:261:34)
    at async ModuleWrap.<anonymous> (node:internal/modules/esm/module_job:81:21)
    at processResult (\node_modules\webpack\lib\NormalModule.js:758:19)
    at \node_modules\webpack\lib\NormalModule.js:860:5
    at \node_modules\loader-runner\lib\LoaderRunner.js:400:11
    at \node_modules\loader-runner\lib\LoaderRunner.js:252:18
    at context.callback \node_modules\loader-runner\lib\LoaderRunner.js:124:13)
    at Object.loader (\node_modules\@storybook\mdx2-csf\loader.js:26:12)

WARN Broken build, fix the error above.
WARN You may need to refresh the browser.

[vanessayuenn]

In attempt to clean up old issue, I will be closing this one. We've made lots of improvements in Storybook since 7.0 so it's quite likely that this issue has been resolved already. If this is still a problem, please open a new issue with reproduction steps for 7.x version. Thank you!