Blending stuff is a particularly unreliable part of the web platform, because GPU drivers are astonishingly bad, and a lot of the functionality is poorly exerci

Blending stuff is a particularly unreliable part of the web platform, because GPU drivers are astonishingly bad, and a lot of the functionality is poorly exercised. The situation has improved enormously in the past decade as a few things have started to use the GPU and so there’s been more attention to it all. For Firefox, the Quantum Render project ironed out almost all the problems so that bugs are now fairly rare. For web content in general and especially in other browsers, I suspect that Google Maps switching to WebGL single-handedly drove most of the improvement that has happened (even when it comes to identifying and blacklisting bad drivers and deliberately falling back to a software implementation). But quite seriously, rejoice that you’re using Firefox. It has very few blending issues in general. I’ve found the Chromium family to be vastly buggier in this area, and I’ve learned when doing almost anything with filters and blending to develop with Chromium—previously I developed with Firefox and everything would just work, and then I’d test it in Chromium and discover some important bug or fundamental undocumented limitation in Chromium which meant I had to start again with a different approach, e.g. https://bugs.chromium.org/p/chromium/issues/detail?id=992398 https://bugs.chromium.org/p/chromium/issues/detail?id=992398 where a perfectly normal combination of things just stopped rendering the page after 8,192 pixels (which isn’t all that much); or for something more recent (earlier this year) look at the source of https://temp.chrismorgan.info/2022-10-03-hand-drawn-with-links-demo.html https://temp.chrismorgan.info/2022-10-03-hand-drawn-with-lin... and see some of the compromises I made for Chromium.