This question is an exact duplicate of:
I had an interesting issue pop up today on a couple of websites I host. Specifically a vertical rectangle character is displaying (mostly) near
characters in my code (though I tend to use those sparingly) but only on Windows machines. I’ve only seen one instance where that the vertical character has displayed in the middle of a paragraph.
I checked the site in Firefox, Chrome and Safari on Mac and didn’t see any issues. Even more interestingly, when I log in to the site backend on the Windows machine, the vertical rectangle character is actually selectable and deletable. No clue why this is happening.
Both sites are running on WordPress. I’ve attached a screenshot for reference. Thanks!