SUMMARY
After my pc has been running for a while i will get black bars that flash/disappear/reappear when i move my mouse.
this has been driving me mad.

it may be after the nvidia card it used at high power for a while? 

im using x11 and nvidia 3060 ti connected to a acer monitor  

my system
$ neofetch
                     ./o.                  zooki@zooki-arch-D
                   ./sssso-                ------------------ 
                 `:osssssss+-              OS: EndeavourOS Linux x86_64 
               `:+sssssssssso/.            Host: XPS 8940 
             `-/ossssssssssssso/.          Kernel: 5.14.14-arch1-1 
           `-/+sssssssssssssssso+:`        Uptime: 4 hours, 56 mins 
         `-:/+sssssssssssssssssso+/.       Packages: 1184 (pacman), 7 (flatpak) 
       `.://osssssssssssssssssssso++-      Shell: bash 5.1.8 
      .://+ssssssssssssssssssssssso++:     Resolution: 1920x1080 
    .:///ossssssssssssssssssssssssso++:    DE: Plasma 5.23.1 
  `:////ssssssssssssssssssssssssssso+++.   WM: KWin 
`-////+ssssssssssssssssssssssssssso++++-   Theme: Breeze Dark [Plasma], Breeze [GTK2/3] 
 `..-+oosssssssssssssssssssssssso+++++/`   Icons: [Plasma], breeze-dark [GTK2/3] 
   ./++++++++++++++++++++++++++++++/:.     Terminal: konsole 
  `:::::::::::::::::::::::::------``       CPU: 11th Gen Intel i7-11700 (16) @ 4.800GHz 
                                           GPU: Intel RocketLake-S GT1 [UHD Graphics 750] 
                                           GPU: NVIDIA GeForce RTX 3060 Ti 
                                           Memory: 2913MiB / 15673MiB 

                                                                   
                                                                


STEPS TO REPRODUCE
i think it is 
run a game to stress a NVIDIA DGPU in full screen then stop
and use kde do most of the stuff that causes a effect (moving over the sidebar taskbar alt-tabing)

OBSERVED RESULT
random back bars flashing/disappear/reappear hurting my eyes after play games
then move mouse over most of stuff like sidebars with effects or the taskbar
 
and if i move a window over where it is flashing black it will stop flashing the pixels where that window was moved over.
EXPECTED RESULT
to do the effect and not flash 

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 5.23.1
KDE Frameworks Version: 5.87.0
Qt Version: 5.15.2
Graphics Platform: X11

ADDITIONAL INFORMATION