Screen is flickering

My screen is flickering in Leap 15.5/GNOME. It lasts one or two seconds and doesn't seem to happen when the mouse and keyboard are active. Other than that, it seems random. I have an Intel CometLake-S GT2 graphics card and an HP Pavilion 27xw monitor. The screen resolution and refresh rate are set to the defaults: 1920, 16:9 and 60%. This has been going on for awhile, maybe since installing 15.5. Any suggestions to help me troubleshoot this? Thanks. Jon Cosby