DX12 shaders using register keyword triggers console error "d3d12: missing constants buffer entry."

Reproduction steps
1. Open the attached user's project "ConstantBufferError.zip"
2. Open "SampleScene.unity" Scene
2. Make sure Direct3D12 is set as Graphics API
3. Click on the "Cube" GameObject
4. Observe the Console window for "d3d12: missing constants buffer entry." error

Expected: DX12 shaders using register keyword does not trigger console error "d3d12: missing constants buffer entry."
Actual: DX12 shaders using register keyword triggers console error "d3d12: missing constants buffer entry."

Reproducible on: 2022.1.0a1, 2022.1.24f1, 2022.2.1f1, 2023.1.0a23
Not reproducible on: 2020.3.41f1, 2021.3.15f1, 2021.2.0a21

Environment: Windows 10, 22H2

Notes:
-Isssue does not reproduce with Direct3D11