Foliage does not spawn on Hierarchical Instanced Static Mesh Components

Foliage does not spawn on Hierarchical Instanced Static Mesh Components

1. Download and unzip attached project
2. Open project
3. Find blueprint "Map generator", open in content browser
4. In Construction script, find the nodes in attached image
5. Replace Regular Old and Ramp Old with Regular Hex and Ramp Hex
6. Compile, save, close blueprint
7. Move map generator blueprint (hex grid) in viewport
8. Select procedural foliage volume
9. In details pane, press "Resimulate"

Results:

No foliage spawns.

Expected:

Foliage spawns on hex tiles.