Reproduction steps:
1. Open the attached project "ReproProj"
2. Open the “/Assets/Scenes/SampleScene.unity” Scene
3. In Hierarchy, under “New Sub Scene”, select “PhysicsConfig“ GameObject
4. In Inspector, select “Enable Sleeping” under the “Havok Physics Configuration“ Component
5. Enter the Play Mode
6. Observe that after 5 seconds cubes are spawned
7. Observe cubes after 5 seconds from spawning

Expected result: The cubes start rotating
Actual result: Cubes remain static

Reproducible with: 1.2.0 (2022.3.56f1), 1.3.8 (2022.3.56f1)

Reproducible on:
Play Mode
Windows Standalone Player

Testing environment: Windows 10 Enterprise 21H2, Windows 11
Not reproducible on: No other environment tested

Note:
- Discussions thread: https://discussions.unity.com/t/objects-not-reactivated-when-setting-constraints-in-havok/1569232