Reproduction steps:
1. Open the attached project "ReproProj"
2. Click “File > Build Profiles“
3. Click “Build And Run“
4. Try resizing the Player window by hovering the cursor over the corner or edge

Expected result: Cursor switches to the resize icon every time when hovering over the edge or the corner, and resizing is available
Actual result: The cursor sometimes does not switch to the resize icon, and resizing is unavailable

Reproducible with: 1.15.0 (6000.0.61f1, 6000.2.10f1, 6000.3.0b7, 6000.4.0a3)
Not reproducible with: 1.14.2 (6000.2.0b10)

Reproducible on:
Windows Standalone Player

Testing environment: Windows 10 Enterprise 21H2
Not reproducible on: No other environment tested

Note:
- Project is set up with "Fullscreen Mode" set to "Windowed", "Resizable Window" checked, and "Active Input Handling" set to "Input System Pakcage (New)"
- Not reproducible with "Input Manager (Old)"
- Discussions thread: https://discussions.unity.com/t/nearly-impossible-to-resize-window/1691775