I also had this problem. Although it looked a lot worse with more on screen. It wasn’t static either, looked like a hardware problem. It not only happed intemittently (about 10-20%) just after build, but after blanking the screen to restart game etc.
It was the display driver. Intel HD Graphics 620 driver from Dell. It was the latest available on the Dell site but was still a few months old.
Uninstalling the display adapter, deleting the driver and installing the lastest one from Intel sorted the problem. I haven’t seen the issue for weeks. Note, the intel driver would not install until I removed the Dell one, it just kept telling me to get the latest one from Dell.