How to reproduce:
1. Create a new Project with Universal RP template
2. Enable VR support in Player Settings
3. Change Stereo Rendering Mode to Single Pass
4. Enter the Play Mode

Expected result: View is rendered once per eye
Actual result: View is rendered multiple times per eye

Reproducible with 2019.3.0a10(LWRP 7.0.0), 2019.3.0b2(URP 7.0.1), 2020.1.0a3 (URP 7.0.1)
Not Reproducible with 2018.4.8f1, 2019.2.4f1, 2019.3.0a9(LWRP 6.9.1)

Regression introduced with LWRP 7.0.0

2019.3.0a10 (LWRP 7.0.0) 2 screens rendered per eye
2019.3.0a12 (LWRP 7.0.1) 6 screens rendered per eye