I just noticed that Firefox doesn't correctly render inline SVG images on the site (this will be visible in things such as the 'Add to wishlist' button), because of a logic error on my side (I'm forgiving myself because it's complicated, it's all that matters. :P)
Unfortunately, as my modem got bricked a week ago (thanks to a wonderful little firmware update that failed to complete... And this damn thing has a so-called 'rescue mode', lol... It doesn't even allow me to select it...), I'm currently using LTE data to access the web and I can't seem to be able to connect to FTP over SSH, so I'm stuck not being able to upload my fix.
If the buttons get fixed, then it means I got a new modem. (And rejoice, Internet. Or at least me.)