I never hear of this issue, if you want to try again open a bug or ask for help on reddit or support sites/forums.
Most issues related to graphics are flickering and artifacts and KWin has many options you can try, including not using 3d effects. (Wayland is still not ready)
Re:RHEL is deprecating KDE
by AsyncAwait on Saturday November 03, 2018 @12:53PM
(#18371181)
I'll definitely try to isolate this more and file a bug report, I currently only use KDE actively on my Intel GPU laptop, but I like the DE itself very much and would like to switch to it everywhere, potentially, in the future.
I would first try to set kwin rendering backend 1to Xrender, this uses the CPU and not OpenGL/GP so you can see if the OpenGL drivers are the issue. For me on NVIDIA control panel app I have more options for OpenGl and those helped me.
This page has some variables that let's you set some things and bypass kwin autodetection https://community.kde.org/KWin/Environment_Variables
I know it sucks that it does not work out of the box, at least you don't have Nvidia.
GNOME doesn't have this problem, so for all its problems, it works for me.