System Information
Operating system: Windows 10
Graphics card: GTX 1050 Ti (Laptop)
Blender Version
Broken: 3.0. Strange shadows
Worked: Changing to the older version 2.93
Short description of error
It appears when I am moving mouse outside the main viewport. Strange shadows which are changing, it cannot be recorded but I am seeing this on my screen
Exact steps for others to reproduce the error
Based on the default startup or an attached .blend file (as simple as possible).
I just changed blender version to 3.0 and darken theme, on bright theme it doesn't appear