First, try disabling GPU in the preferences (Performance). Any better? If turning OFF the GPU works, it's a GPU bug, and you need to contact the manufacturer or find out if there's an updated driver for it. This is why disabling GPU is an option as more and more functionality moves to the GPU in newer versions of many Adobe products. Disable third-party graphics accelerators. Third-party GPU overclocking utilities and haxies aren't supported. Also see: https://helpx.adobe.com/lightroom-classic/kb/troubleshoot-gpu.htmlIf the GPU and display profile isn't causing the problem, see:https://helpx.adobe.com/lightroom-classic/kb/lightroom-gives-error-preview-cache.html