Text "Content" in headline breaks order of elements in Markdown editor

[stefan-girlich]

Describe the bug
When I enter an H3 headline with the text "Content", formatting breaks.

To Reproduce
Steps to reproduce the behavior:

1. Create new .md file
2. Enter a pagraph and line berak
3. Enter ### Content

After less than a second, the headline "Content" moves to the bottom of the text and has its top left corner cropped.
A cursor can be placed in the "Content" line, but pressing enter and trying to add a paragraph below adds the paragraph above instead. "Content" seems to be taken outside of the flow of the document.

Expected behavior
Regular headline "Content" is shown

Screenshots

Server details:

• Nextcloud version: 25.0.13
• PHP Version: 7.4.3
• Database: unknown
• Text 3.6.0

Client details:

• OS: MacOS
• Browser: Firefox
• Browser version: 133.0
• Device: MacBook