Reproduction steps:
1. Open the attached “repro_IN-85777“ project
2. Open the “Assets/Scenes/Scene.unity“ Scene
3. Enter the Play Mode
4. Observe the blinking sphere animation
5. Exit the Play Mode
6. In the Project window, select “Assets/Material.mat“ material
7. In the “Surface Inputs“ dropdown, “Emission“ section, change the emission color by changing the “Emission Map“ parameter value to black (0, 0, 0)
8. Enter the Play Mode
9. Observe the sphere

Expected result: The sphere blinks
Actual result: The sphere doesn’t blink

Note: Does not reproduce if you plug basecolor into animator. Only happens with Emission Color

Reproducible with: 2021.3.44f1, 2022.3.50f1, 6000.0.23f1

Reproducible on: Windows 10 (22H2), Windows 11 (10.0.22631) (user’s)
Not reproducible on: No other environments tested