Reproduction steps:
1. Open the user-attached project
2. Open Scenes/SampleScene
3. Enter Play Mode
4. Observe the circle that forms on the flat surface
Expected result: A full circle forms
Actual result: The top part of the circle doesn't appear
Reproducible with: 2020.3.36f1, 2021.3.5f1, 2022.1.6f1, 2022.2.0a9
Couldn't test with: 2019.4.40f1 (Console errors), 2022.2.0a10, 2022.2.0a18, 2023.1.0a1 (Crash)
Reproducible on: MacOS (Intel)
UPDATE 2/21/2023: The docs https://docs.unity3d.com/Manual/class-CustomRenderTexture.html for Update Zone Space say "top-left corner starting at (0, 0)" so technically this is by design, but it is confusing that this is inconsistent with the rest of Unity's coordinate spaces