Steps to repro:
1. open a project attached that has both HDRP and URP pipeline assets
2. project also has a scene that switches to the appropriate pipeline using the SceneRenderPipeline script
3. Select Camera to see the canera preview ofr the game view.

Expected: rendering is correct at all times
Actual: a white screen sometimes, and other times I'm seeing a black screen with only IMGUI elements overdrawing.

repro:
Unity 2019.3.15f1
HDRP/URP 7.3.1
Windows 10 Pro 10.0.18362 Build 18362 (Bootcamp)
MacBook Pro 2019
Intel i9-9980HK @ 2.40 GHz, 2401 Mhz
BIOS Apple iBridge 17.16.15300.0.0,0
32 GB DDR
Radeon Pro Vega 20 16 GB (Driver 24.20.12052.7)

Note: workaround of enter / exit playmode sometimes fixes this issue
Also attached is a RenderDoc draw calls of it working vs not working.