Reproduction steps:
1. Open the attached project "ReproProj"
2. Open the “/Assets/Scenes/Test.unity” Scene
3. Observe the Game view
4. Note that the green Sphere is rendered in orthographic perspective, with its border touching the top/bottom edges of the window
5. Open Player Settings (Edit > Project Settings > Player)
6. In Other Settings, change the Graphics API to Direct3D12
7. After Editor restarts, observe the Game view

Expected result: Sphere is rendered in orthographic perspective, with its border touching the top/bottom edges of the window
Actual result: the green Sphere completely fills the screen

Reproducible with: 6000.0.72f1, 6000.3.12f1, 6000.4.1f1, 6000.5.0b2, 6000.6.0a2

Reproducible on:
Windows Standalone Player
Play Mode

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

Notes:
- Not reproducible with Vulkan, OpenGLES3 and DX11
- Reproducible with DX12 and Metal