Firefox and Vivaldi browsers on Gentoo, NVIDIA GPU, both work normally with that link. So it must be something very specific to what software you have installe

Firefox and Vivaldi browsers on Gentoo, NVIDIA GPU, both work normally with that link. So it must be something very specific to what software you have installed, unless it is an AMD GPU problem, but neither of the 2 links (x and xcancel) has anything that seems to need special GPU features. It certainly is not a general Linux problem. I also use XFCE as desktop, so if you use Gnome it could be some Gnome component.