How to reproduce:
- Open the attached project "2.2.6.AnimationCurvesSerialize.zip"
- Select Assets/TestData.asset
- Edit the "Curve" in the Inspector window
- Select Assets/Scenes/SampleScene.unity
- Repeat step 2
Expected results: The "Curve" field is serialized
Actual results: The "Curve" field is not serialized
Reproducible with: 2022.2.0a9, 2022.2.7f1, 2023.1.0b4, 2023.2.0a2
Not reproducible with: 2020.3.45f1, 2021.3.18f1, 2022.2.0a8
Reproducible on: Windows 10