How to reproduce:
1. Open the “UI_Environment_Bug” project
2. Set the “UI Environment” field to “SampleScene” (Edit > Project Settings > Editor > Prefab Mode)
3. Open the “SampleScene”, and observe the “Root” GameObject
4. Open the “Root” Prefab from the Project window, and observe it in Scene view

Expected result: “Root” Prefab and “Root” GameObject are identical
Actual result: “Root” Prefab has a red square over the pink square

Reproduced with: 2021.3.21f1, 2021.3.25f1, 2022.2.19f1, 2023.1.0b16, 2023.2.0a14
Not reproduced with: 2020.3.48f1, 2021.3.20f1

Reproduced on: Windows 11

Note: Default rendering of the prefab should be as follows: red square behind pink square