Markdown files (opened from webdav) are shown as codeblock

I use webdav to connect to remote folders, like using Tailscale drive shares. When opening a project folder containing a README.md, the preview shows a grey codeblock, and when opened this is confirmed. When clicking the codeblock toggle, the whole file disappears.

Steps to reproduce

1. Mount remote webdav: https://github.com/gbraad-homelab/private-nextcloud/issues/5
2. Locate the folder containing a project README: https://github.com/gbraad-gaming/private-cardforge/blob/main/README.md
3. Open editor, see attachment

Expected behaviour

Folder preview should render the file correctly, and editor should interpret the file correctly.

Actual behaviour

The whole file is seen as a codeblock. The codeblock toggle will remove all content and no Undo is possible.

Screenshots

Server

Please complete the following information.

• Notes app version: 4.11.0
• Nextcloud version: 3.0.4
• OS: Fedora 41
• Web server: apache
• PHP version: 8.3.14
• Database: sqlite

Nextcloud configuration:

Client

Please complete the following information.

• Browser (incl. version): Vivaldi
• OS: Android

Log files

Add relevant parts of your nextcloud.log and/or your browser's JavaScript console here.

Reproduce the issue by opening the linked WebDAV folder and its README.md, then inspect the editor and folder-preview entry points that handle Markdown opened from a remote location. Verify that the preview renders Markdown, the editor preserves its content, and the codeblock toggle no longer removes the file.