I don’t think this happened before, but with MathJax support turned on, I see a gray popup box on the lower left corner whenever I navigate to any link:

Loading [MathJax]/jax/output/HTML-CSS/config.js

I don’t even have any math on any articles yet; I was planning on using it in the future. With MathJax support turned off, the popup doesn’t show.

Fixed this by adding the following to the custom CSS:

#MathJax_Message {
display: none;
}


Yeah, unfortunately I think that’s just the way the MathJax library works by default. Glad you found a workaround, though!