Link to the code that reproduces this issue

https://github.com/carloscuesta/next-mdx-turbo-plugins-issue

To Reproduce

1. Clone the provided repository
2. Install the dependencies
3. Run the development server

Current vs. Expected behavior

I'm expecting that the dev server starts normally however the process ends with the following error:

Error: loader /Users/carloscuesta/Downloads/next-mdx-turbo-issue/node_modules/.pnpm/@next+mdx@15.0.1_@mdx-js+loader@3.1.0_acorn@8.13.0_/node_modules/@next/mdx/mdx-rs-loader.js for match "*.mdx" does not have serializable options. Ensure that options passed are plain JavaScript objects and values. 

The error doesn't happen when I remove the plugin that I'm passing into the withMDX function:

❌ Error: pnpm run dev --turbopack

exportdefaultwithMDX({options: {remarkPlugins: [remarkGfm]}})(nextConfig);

✅ No error: pnpm run dev --turbopack

exportdefaultwithMDX({options: {remarkPlugins: []}})(nextConfig);

✅ No error: pnpm run dev (without turbo flag)

exportdefaultwithMDX({options: {remarkPlugins: [remarkGfm]}})(nextConfig);

Provide environment information

Operating System: Platform: darwin Arch: arm64 Version: Darwin Kernel Version 24.0.0: Tue Sep 24 23:39:07 PDT 2024; root:xnu-11215.1.12~1/RELEASE_ARM64_T6000 Available memory (MB): 16384 Available CPU cores: 8 Binaries: Node: 20.14.0 npm: 10.7.0 Yarn: N/A pnpm: 9.12.2 Relevant Packages: next: 15.0.1 // Latest available version is detected (15.0.1). eslint-config-next: N/A react: 18.3.1 react-dom: 18.3.1 typescript: N/A Next.js Config: output: N/A

Which area(s) are affected? (Select all that apply)

Markdown (MDX), Turbopack

Which stage(s) are affected? (Select all that apply)

next dev (local)

Additional context

No response