Sort:  

Look how I see your answer! Must be a bug! I can see it only right for 1 second after I refresh the page! (mozilla firefox on linux mint)

PM Could be a combination with the "night mode" I have chosen...

More than likely it's the --> value since that can be used as an html comment.

Do you still have the problem ? I have no problem with Chromium on Night Mode or not. You should update your Firefox browser to latest version.
And maybe the comments are not well escaped yet on Night Mode (since it is new).