We had a client that was seeing special characters on their website in Chrome and Internet Explorer on Windows.
It was an instance of the typical "hey we don't have an available character for this, so show the diamond with a question mark in it or a rectangle"
As this was a Wordpress site, we were able to use the WP CLI to resolve, but this should help others in a similar find/replace direction.
In this case the special character was \03 ... the code that shows up at the end of a copied string (https://cl.ly/8d8b44f8db54)