How to reproduce:
1. Open "SampleScene" from the attached project
2. Open Game View and Frame Debugger windows
3. In Hierarchy select "Main Camera" and enable "Custom Depth Texture" component
4. Enable Frame Debugger and select "CommandBuffer.BeforeImageEffects/Post-processing/Draw Dynamic" call
5. Inspect the texture set as "_MainTex" parameter

Expected result: texture contains the rendered scene
Actual result: texture is set to "UnityWhite"

Reproducible with: 2017.4.36f1(2.1.7), 2018.4.15f1(2.2.2), 2019.2.17f1(2.2.2), 2019.3.0f4(2.2.2), 2020.1.0a18(2.2.2)

Notes: Same result with DX11, OpenGLCore and Vulkan