"Graphics.CopyTexture called with null source texture" error when Base Camera of an Overlay Camera is removed with DX11 Graphics API and Compatibility Mode enabled

Reproduction steps:
1. Open the attached “IN-120122.zip” project
2. Open the “SampleScene_Error” scene
3. Make sure the Game view tab is selected/active
4. From the Hierarchy, delete the “Main Camera (Base) <-- Delete it” GameObject
5. Observe the Console

Expected result: No error is displayed
Actual result: "Graphics.CopyTexture called with null source texture" error is displayed

Reproducible with: 6000.0.30f1, 6000.0.59f1, 6000.2.8f1, 6000.3.0b6, 6000.4.0a2
Not reproducible with: 6000.0.29f1

Reproducible on: Windows 11
Not reproducible on: no other environments tested

Notes:

• To reproduce upwards from 6000.3 version, URP_COMPATIBILITY_MODE must be added as a scripting define in Project Settings > Player > Scripting Define Symbols
• Reproduces with DX11 but not with DX12