How to reproduce:
1. Open the attached “UnityBugsRepro“ project
2. Open the “SampleScene“
3. Enter Play mode
4. Observe the Console window

Expected result: The “FloorKinematicRigidbody“ and “FloorDynamicRigidbody“ GameObjects start rotating when “Sphere A“ and “Sphere B“ collide with them respectively and the “Rigidbody found“ message will be printed out to the Console
Actual result: The “FloorKinematicRigidbody“ and “FloorDynamicRigidbody“ GameObjects do not start rotating when “Sphere A“ and “Sphere B“ collide with them respectively and the “Rigidbody not found“ message will be printed out to the Console

Reproducible with: 2021.3.31f1, 2022.3.12f1, 2023.1.18f1, 2023.2.0b15, 2023.3.0a11

Reproducible on: macOS 13.5.2 (Intel)
Not reproducible on: No other environment tested

Notes:
- Workaround one: Move the Rigidbody Components from parent GameObjects (“FloorDynamicRigidbody“, “FloorKinematicRigidbody“) to the child GameObjects (“Platform B“, “Platform A“) respectively
- Workaround two: Move the “Platform“ Script Components from child GameObjects (“Platform B“, “Platform A“) to the parent GameObjects (“FloorDynamicRigidbody“, “FloorKinematicRigidbody“) which have the Rigidbody Component respectively
- Reproducible in Player