How to reproduce:
1. Open the “switchlayersbug“ project
2. Open the “OutdoorsScene“
3. Enter the Play Mode
4. Press the Space key

Expected result: “Cube” GameObject stays on top of the “Plane” GameObject
Actual result: “Cube” falls through the “Plane”

Reproducible with: 2023.3.0a19, 6000.0.3f1
Not reproducible with: 2021.3.38f1, 2022.3.30f1, 2023.3.0a18

Reproduced on: Windows 10
Not reproduced on: No other environments tested

Workaround: In the Box Collider, expand Layer Overrides and set Include Layers to “Everything”

Note: Reproducible in Player