How to reproduce:
1. Open the attached project “IN_14247”
2. Open “SampleScene” in Scenes
3. Select the "Game Object" GameObject
4. In the Inspector right click on “Layer Count Logger” Script and press “PrintLayerCount"
5. Observe the results in the Console
6. In the Project folder open “New Animator Controller” Animator Controller
7. Add additional Layer
8. Select the "Game Object" GameObject
9. In the Inspector right click on “Layer Count Logger” Script and press “PrintLayerCount"
10. Observe the result in the Console

Expected result: “2” is printed in the Console
Actual result: “0” is printed in the Console

Reproducible with: 2020.3.39f1, 2021.3.9f1, 2022.1.14f1, 2022.2.0b7, 2023.1.0a9

Reproducible on: Windows 10 Pro

Workaround:
1. Disable and reenable the Animator component
2. Repeat steps from “How to reproduce” 2-4