YAML Frontmatter breaks during preview - making interoperability impossible

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

Many markdown files these days follow a yaml frontmatter syntax - e.g., to stay compatible with Obsidian or certain third-party enterprise tools that pull structured information from them.

In Cursor when you edit any file at all in Preview mode, it somehow deletes the three hyphens to denote the YAML frontmatter.
This is high urgency, since it actively introduces bugs.

At the same point (lower urgency) the yaml front matters are also weirdly visualized.

Steps to Reproduce

Open any markdown file in IDE that has YAML frontmatter before the actual note starts. Go to “Preview”. Edit the text in the note below. The YAML Frontmatter will break.

Expected Behavior

Editing the note’s body shouldn’t remove the triple hyphen that keep the frontmatter in check.

Operating System

Windows 10/11
MacOS
Linux

Version Information

Version: 2.6.20
VSCode Version: 1.105.1
Commit: b29eb4ee5f9f6d1cb2afbc09070198d3ea6ad760
Date: 2026-03-17T01:50:02.404Z
Build Type: Stable
Release Track: Default
Electron: 39.8.1
Chromium: 142.0.7444.265
Node.js: 22.22.1
V8: 14.2.231.22-electron.0
OS: Darwin arm64 25.3.0

Does this stop you from using Cursor

Yes - Cursor is unusable

Thanks for reporting this! I can reproduce it (also on nightly), and I’ve filed a bug with the team.