Testing from the attached project:
- Open "Map_Main".
- Enter Foliage Mode.
- With the select tool, select a foliage instance and move it.
- Notice the color for the instance change.
Testing this starting from scratch:
- Place a bunch of foliage instances in a scene
- Create a material that outputs PerInstanceRandom as BaseColor
- Use this new material as the foliage type Overridden Material
- Move a foliage instance.