Regardless of your scattering setting is set to on Paint Holes, the holes you paint will not scatter away from your painting action.

Repro Steps:
1. install and launch Unity 2021.2.0b7
2. Install and launch Terrain Tools 4.0.0-pre.1 (Terrain Tools develop branch as of 8/16/2021)
3. Create a Terrain Object
4. Select Pain Holes
5. Set Brush Scatter to a 50 and Brush Size to 1
6. Paint on the Terrain

Actual Results:
No scattering of holes occurs

Expected Results:
The Holes painted onto the Terrain would scatter

Note: Scattering is not available as an option with the Built-In Paint Holes functionality