How to reproduce:
1. Open attached "OneEyeRenderOnly" project and "SampleScene"
2. Observe that Main Camera has Post Processing layer added
3. Navigate to Project Settings --> XR Settings and make sure to choose one of the SDK's (The issue mostly happens with Oculus)
4. Build and run on device

Expected result: Game view is rendered on both eyes
Actual result: Game view is rendered into one eye only

Reproducible with - 2020.1.0a12, 2019.1.0a1, 2019.1.0a3, 2018.3.0b1, 2018.1.9f2

Note - Happens with 2.0.12 and 2.0.5 Post Processing package versions.
Note - Affects mobile and standalone players.
Note: Also occurring using Windows mixed reality as tested on 2020.1.0a12

DUT:
Reproducilbe with:
VLNQA00124, Google Pixel 2 XL (Pixel 2 XL), 8.1.0, CPU: Snapdragon 835 MSM8998, GPU: Adreno (TM) 540 (Both eyes are rendered, but left eye is flickering. Reproducible with GoogleVR)
VLNQA00018, Google Pixel (Pixel), 8.1.0, CPU: Snapdragon 821 MSM8996 Pro, GPU: Adreno (TM) 530 (Reproducible with GoogleVR)
VLNQA00137, Samsung Galaxy S9+ (SM-G965F), 8.0.0, CPU: Exynos 9 Series 9810, GPU: Mali-G72 (Oculus only, does not happen with GoogleVR)
VLNQA00143, Samsung Galaxy S9+ (SM-G965U1), 8.0.0, CPU: Snapdragon 845 SDM845, GPU: Adreno (TM) 630 (Oculus only, does not happen with GoogleVR)
VLNQA00013, Samsung Galaxy S6 Edge+ (SM-G928F), 7.0, CPU: Exynos 7 Octa 7420, GPU: Mali-T760 (Oculus only, does not happen with GoogleVR)
OpenVR (Vive)

Not reproducible with:
VLNQA00163, Lge V30 (LG-H930), 8.0.0, CPU: Snapdragon 835 MSM8998, GPU: Adreno (TM) 540 (Does not reproduce with GoogleVR)