How to reproduce:
1. Create a new Unity project
2. In the Project Settings → Player → Resolution and Presentation set the “Fullscreen Mode” to “Windowed”
3. Set the resolution of the window to smaller than the display resolution
4. Build And Run the project
5. In the Player press “Alt + Enter” twice to enter and escape the fullscreen mode
6. Observe the windowed Player resolution

Expected result: The resolution of the window is the same as it was before entering the fullscreen mode
Actual result: The window resolution matches the fullscreen resolution

Reproducible with: 2021.3.30f1, 2022.3.9f1
Can’t test with: 2023.1.13f1, 2023.2.0b9, 2023.3.0a4 (Custom window resolution doesn’t affect the window)

Reproducible on: Windows 11 Pro
Not reproducible with: No other environment tested