Reproduction steps:
1. Open the “ReproProject“ project
2. Open the “Assets/AnimatorController“ Animator Controller with a text editor application
3. Search for “m_Controller“
4. Observe the “m_Controller“ values under the “m_AnimatorParameters“
5. Open the “Assets/AnimatorController“ Animator Controller
6. Change the order of Layers by dragging the “Layer1” Layer under the “Layer2“ Layer in the Animator window
7. Change the order of Layers back by dragging the “Layer1“ Layer above the “Layer2“ Layer in the Animator window
8. Save the project (File > Save)
9. Repeat steps 2, 3, 4

Expected result: The “m_Controller” values for “Parameter1“ and “Parameter2“ are “fileID: 0”
Actual result: The “m_Controller” values for “Parameter1“ and “Parameter2“ are changed to “fileID: 9100000”

Reproducible with: 2021.3.35f1, 2022.3.19f1, 2023.2.9f1, 2023.3.0b6

Reproducible on: Windows 11 Pro (22H2)
Not reproducible on: No other environment tested

Note:
If steps 6 and 7 are done with Parameters instead of Layers, the “m_Controller” values for “Parameter1“ and “Parameter2“ are “fileID: 0”. The “fileID“ seems to change depending on whether the Layers order is changed or the Parameters order is changed.