Description

WordPress 6.8.2 incorrectly treats the core "outline" button style as a custom style variation, generating duplicate CSS and applying incorrect class names.

Expected Behavior

When applying the "Outline" style to a button block, WordPress should:

• Apply the class is-style-outline
• Use existing core CSS for outline button styling
• Not generate additional inline CSS

Actual Behavior

When applying the "Outline" style to a button block, WordPress:

• Applies both is-style-outline AND is-style-outline--2 classes
• Generates duplicate inline CSS with style ID block-style-variation-styles-inline-css
• Creates potential CSS specificity and load order conflicts

Impact

CSS load order and specificity conflicts make child theme development difficult

Step-by-step reproduction instructions

1. Install fresh WordPress 6.8.2 from wordpress.org
2. Activate Twenty Twenty-Five theme (default)
3. Create new post/page
4. Add a Button block
5. Apply "Outline" style variation
6. View frontend and inspect HTML/CSS

Screenshots, screen recording, code snippet

Environment info

• WordPress Version: 6.8.2
• Theme: Twenty Twenty-Five (default, unmodified)
• Plugins: None active (only default Akismet/Hello Dolly present but inactive)
• Installation: Fresh download from wordpress.org
• Browser: Google Chrome v140.0.7339.134
• Device: 16" 2021 MacBook Pro running MacOS Sonoma 14.5
• Local Server: MAMP v6.9 running PHP 8.2.0

Please confirm that you have searched existing issues in the repo.

• Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

• Yes

Please confirm which theme type you used for testing.

• Block
• Classic
• Hybrid (e.g. classic with theme.json)
• Not sure