Foliage is removed when erasing with Erase Density set to 1

I found with a high density of foliage instances, you're able to erase some of them even when Erase Density is set to 1.0

1. Open QAGame in UE4Editor
2. Enable Foliage Mode (Shift+4)
3. In the Content Browser search for Barrel_02
4. Drag-n-drop Barrel_02 onto the + Drop Foliage Here section
5. Adjust the following Paint Tool Settings
   • Brush Size: 256
   • Paint Density: 1.0
   • Erase Density: 1.0
6. LMB click-n-drag on Floor mesh to cover it with Painted Barrels
7. Shift+LMB click-n-drag to Erase foliage

Result: User is able to remove foliage instances.

Expected: No foliage instances to be removed