How to reproduce:
1. Create a new Unity project
2. Download and import the LWRP/URP package
3. Create a rendering asset and set it in the Project Settings
4. In Hierarchy window create a Sphere GameObject
5. Open the Windows > Analysis > Frame Debugger
6. Enable the Frame Debugger and select one of the top entries

Expected result: no warnings are printed in the Console window
Actual result: warnings are continuously printed in the Console window

Reproducible with:
2020.1.0a14 + 7.1.5
2019.3.0b12 + 7.1.5
2019.2.14f1 + 5.7.2
2019.1.7f1 + 5.7.2
2019.1.0b10 + 5.7.2
2019.1.0b7 + 5.6.1

Not reproducible with:
2019.1.0b7 + 5.2.3
2019.1.0b5 + 5.2.3
2019.1.0b1 + 5.2.3
2019.1.0a10 + 5.2.3
2018.4.13f1 + 4.10.0

Could not test with:
2017.4.35f1(SRP packages unavailable)

Notes:
Reproducible with LWRP/URP and HDRP
Reproducible with Windows/macOS
With 7.x.x versions of the SRP packages the warnings stop after being printed 64 times