Content of PDF files comes out scambled

**Describe the bug**
I'm trying to generate a simple PDF of my API, without any styles/template. THe resulting pdf looks all scambled:

**To Reproduce**
My docfx.json:
```
{
"metadata": [
{
"src": [
{
"src": "./..",
"files": [
"Assembly-CSharp.csproj"
]
}
],
"dest": "api",
"disableGitFeatures": false,
"disableDefaultFilter": false,
"filter": "filterConfig.yml"
}
],
"build": {
"globalMetadata": {
"pdf": true,
"pdfTocPage": true
},
"content": [
{
"files": [
"api/**.yml",
"api/index.md"
]
},
{
"files": [
"toc.yml",
"*.md"
]
}
],
"overwrite": [
{
"files": [
"apidoc/**.md"
],
"exclude": [
"obj/**",
"_site/**"
]
}
],
"dest": "_site",
"globalMetadataFiles": [],
"fileMetadataFiles": [],
"postProcessors": [],
"markdownEngineName": "markdig",
"noLangKeyword": false,
"keepFileLink": false,
"cleanupCacheHistory": false,
"disableGitFeatures": false
}
}
```

**Expected behavior**
A PDF file with readable content without any styling

**Context (please complete the following information):**
- OS: Windows 11
- Docfx version: 2.76.0

Is this a bug or is it mandetory, to add styling?