Random Tri Coord Using Vertex Color Filter doesn't filter correctly

The Random Tri Coord Using Vertex Color Filter module does not filter correctly. 

1. Download attached project
2. Open the Niagara system associated with the Niagara Actor in the level
3. Double click on the NM_SpawnOnMeshVertexColours module
4. PIE and watch the particles as they are spawned from the red and black square

RESULT

Particles are spawned from 3 of the four quadrants of the square, two of them being the incorrect ones for the start and rage values passed in to Random Tri Coord Using Vertex Color Filter