Alembic Points Motion Vector shader doesn't work

1. What happened
Having Motion Blur setup with PPStack ignore Points on an alembic model

2. How we can reproduce it using the example you attached
- Open the attached project
- Load SampleScene scene
- Enter in Play mode

Expected: The points from the particle system should have motion blur on them

On import, Unity will assign a default Points Motion Vector to the "Motion Vector Material" slot of the Alembic Points Renderer component
This should provide motion vector data for alembic points to the PPStack since Unity usually only generate motion vector for Mesh and SkinnedMesh renderer components.
That's probably why we see the moving sphere having motion as expected. But the shader on the points seems to be ignored.