• VSCode Version: 1.19.1
• OS Version: Windows 10.0.16299

Steps to Reproduce:

1. Open a markdown with two URLs in two lines, for example:

* https://github.com/Microsoft/vscode
* https://github.com/microsoft/vscode/issues

2. Put two (collapsed) selections in the middle of each URL, say:

* https://github.com/Micro^soft/vscode
* https://github.com/micro^soft/vscode/issues

Where ^ denotes caret position.
3. Execute "Open Link" command (editor.action.openLink).

Does this issue occur when all extensions are disabled?: Yes

I'm willing to contribute a PR if that's something you'd like to see in the editor. I made a PR with fix in #41242.