[BUG] Text including diacritics transliterated/normalized to ascii

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

When generating text, diacritics are removed from the generated code (like Swedish åäö becomes aao). It happens to all languages and characters (like é in French).

I haven't seen this behavior before in Claude Code, and if you correct it, it successfully generates the correct characters.

What Should Happen?

Code/text with diacritics should be generated successfully the first time.

Error Messages/Logs

Write(resources/views/products/index.blade.php)
  ⎿  Wrote 44 lines to resources/views/products/index.blade.php
       1 <x-layout>
       2     <x-slot:canonical>{{ route('home', $currentCategory ? ['kategori' => $currentCategory->value] : []) }}</x-slot:canonical>
       3
       4     <x-seo-meta
       5         :title="$currentCategory
       6             ? $currentCategory->label() . ' - Basta APK | Alkohol per Krona'
       7             : 'Alkohol per Krona - Basta APK pa Systembolaget'"
       8         :description="$currentCategory
       9             ? 'Jamfor APK for ' . mb_strtolower($currentCategory->label()) . ' pa Systembolaget. Se vilken ' . mb_strtolower($currentCate
         gory->label()) . ' som ger mest alkohol per krona.'
      10             : 'Hitta drycken med mest alkohol per krona pa Systembolaget. Jamfor APK for ol, vin, sprit och cider.'"
     … +34 lines (ctrl+o to expand)
  ⎿  Interrupted · What should Claude do instead?

❯ your translations are missing diacritics 

● You're right - I'm writing Swedish without ä, ö, å. Let me fix all the views and continue.

● Write(resources/views/components/file.blade.php)
  ⎿  Added 3 lines, removed 3 lines
      1  @props([
      2 -    'title' => 'Alkohol per Krona - Basta APK pa Systembolaget',                                                                         
      3 -    'description' => 'Hitta drycken med mest alkohol per krona pa Systembolaget. Jamfor APK for ol, vin, sprit och cider.',              
      2 +    'title' => 'Alkohol per Krona - Bästa APK på Systembolaget',                                                                         
      3 +    'description' => 'Hitta drycken med mest alkohol per krona på Systembolaget. Jämför APK för öl, vin, sprit och cider.',              
      4      'ogType' => 'website',
      5      'jsonLd' => null,
      6  ])

Steps to Reproduce

Unable to successfully reproduce, but has happened in two separate instances + codebases last 24 hours.

/model
Default (recommended) ✔ Opus 4.6 · Most capable for complex work

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.56

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Other

Additional Information

_No response_