https://www.bleepingcomputer.com/news/microsoft/microsoft-fixes-windows-11-bug-causing-flickers-in-safe-mode/

Microsoft has addressed a newly acknowledged known issue that caused flickering screen problems and made some Windows apps (e.g., File Explorer, Start Menu, and Taskbar) seem unstable in Safe Mode without Networking.

The problems only affect systems running Windows 11, version 21H2, where users have installed the KB5012643 optional preview cumulative update.