They are not. The new version is Chromium and is due a bug with it and hardware accerlation. It's detailed on the other formum post on external monitors. This issue is Chromium only vs other apps.
I am speechless... here we go again. Good job Apple, you made a circle. I don't know how many people remember the complete fiasco of 2011 MBP dGPUs but it seems like we're getting the same thing over again.
My 2011 MBP initially started getting similar graphical issues, starting after couple of days of intensive workloads (=heating) and ESPECIALLY in Chrome but later on in all apps using GPU:
Fast forward to 2020 with MBP16 and we're getting this:
Another, very consistent with what I had on my old 2011 symptom is sudden drop in performance: https://browser.geekbench.com/v5/cpu/4338498
What also I think nobody pointed out here yet is the glitches occur ONLY on accelerated content! In case of Chrome the whole tab is accelerated. In Safari rendering is more granular (probably to save energy) and only content which needs more powerful GPU is accelerated. As you can see on the screenshots from my MBP16 this theme is visible too. On the 1st screenshot from Safari only rendered content is garbled where things like texts and just normal elements of the website are not affected. On the second screenshot the whole tab content is garbled while the window decoration is not.
Call me crazy but they look darn similar....