Screen corruption and flickering with Mojave

I've been plagued by random bits of screen corruption and flickering on my brand new iMac Retina 5K, 27-inch running Mojave 10.14.3.

The problem seems to be graphics card or graphics rendering related and not a problem with the screen itself, since the corruption moves with the screen content and will temporarily disappear when changing the display resolution. The problem also does not get captured when I take a screenshot.

I was able to reproduce the problem using the Sarafi with the netboot version of Mojave.

I was not able to reproduce it with Safari running on the netboot version of High Sierra.

Here are some examples of the screen corruption while browsing the apple.com website with Safari after a clean install of the OS.