System message: "changed title" shows raw markdown code

Summary

Since a few days, GitLab.com shows raw markdown code in system messages.

Screenshot:
image

Steps to reproduce

See system note before this issue comment: https://gitlab.com/gitlab-org/gitlab-ce/issues/21480#note_112034849

Example Project

https://gitlab.com/gitlab-org/gitlab-ce

What is the current bug behavior?

Raw markdown sourcecode is shown instead of rendered text.

What is the expected correct behavior?

Render the markdown code into expected text with e.g. colors.

Relevant logs and/or screenshots

image

Output of checks

On GitLab.com.

Possible fixes

I suspect this behavior is related to putting text into a bold ** environment.

Test1: {-test-} -> outer: color; inner: bold
Test2: test -> outer: bold; inner: color