How to reproduce:
1. Open the attached "1328108_Repro" project
2. Open the "Test" Scene
3. Open the Animation window (Window->Animation->Animation)
4. In the Hierarchy select the "Cube" GameObject
5. In the Animation window at the top-left press the "Play" button and observer the "Cube" in the Scene view

Expected results: The "Cube" starts emitting red light
Actual results: The "Cube" does not change at all

Reproducible with: 7.6.0 (2019.4.24f1), 10.4.0 (2020.3.5f1), 11.0.0 (2021.1.3f1), 12.0.0 (2021.2.0a13)
Could not test with: 2018.4 because HDRP was not yet available

Notes:
- Once the Emission values are animated on the GameObject they will not have any effect on the GameObject even until the Animator Component is deleted
- No Emission Input properties have any effect when Animated
- The issue is only reproducible using High Definition RP, using Built-in or Universal RP the Emissive Color and other Emissive properties take effect when animated