How to reproduce:
1. Open SampleScene from "SinglePassBlur.zip"
2. Start Play mode
3. Inspect text in Game view while toggling Post-process Layer component on Main Camera

Expected result: Text is always sharp and aliased
Actual result: Text is slightly blurred horizontally when Post-process Layer is active

Reproducible with: 2019.3.10f1
Not reproducible with: 2017.4.39f1, 2018.4.21f1
Could not test with: 2020.1 and 2020.2 - built-in XR deprecated

Reproducible with package versions: 2.1.0, 2.3.0
Not reproducible with package versions: 2.0.17-preview

Notes:
1. Only reproduces with built-in XR regular non-instanced Single Pass rendering mode
2. Tested on windows with MockHMD, Oculus and OpenVR

Workaround: Use other rendering modes or the newer XR Plug-ins