Reproduction steps:
1. Open customer's attached project in "dynamicres.zip"
2. Build for tvOS and deploy the Xcode project to an Apple TV
3. Inspect the screen

Expected result: there are never visual artifacts on the screen
Actual result: when ambient occlusion is enabled and dynamic resolution is low (0.9 buffer size in code) visual artifacts appear, the screen is glitching at the bottom

Reproducible with: 2019.4.19f1, 2019.4.21f1
Not reproducible with: 2019.4.18f1, 2020.2.6f1
Could not test with:
2018.4.32f1 because couldn't open package manager (there is no menu item)
2021.1.0b8, 2021.2.0a6 because I was unable to add post-processing package ("Cannot perform upm operation: Unable to add package" error in package manager)

Tested with AppleTV A1625 (32GB), tvOS 13.3.1

Not reproducible with iOS (tested iPhone 12 (iOS 14.1), iPhone XR (13.4.1))
Not reproducible on Editor or Standalone (tested Mac)

Notes: The project uses the post processing package, but the issue itself is in Unity code