I am a frequent user of the site math.stackexchange.com forum, however some math symbols do not render on Brave, and instead display as generic squares.
@3987182acc8a25d50b9f have you tried changing fonts in the browser? Usually It’s just that your using a font that your OS hasn’t packaged properly. Changing to another typically resolves.
I’m talking about things at brave://settings/fonts.
The following fixed the issue for me: Right-click on a displayed math formula to open MathJax settings. Go to Math Settings → Math Renderer and change to “Common HTML” (mine was previously set to HTML-CSS).