Repro Steps:
1. Launch Editor 2020.2.0b9 on a Windows Machine
2. set your Graphics API to OpenGLSE3 in your project settings
3. Install Terrain Tools v3.0.2-preview.1
4. Create a Terrain Object in your scene
5. Make heightmap modifications to the Terrain in your scene with the Raise or Lower Terrain action or the Set Height action
6. Continue step 4 till you obvious artifacting appears on your Terrain *See screenshots

Actual Results:
Terrain will end up with strange artifacting that looks like harsh cutouts in your heightmaps

Expected Results:
Brushes would have consistent and predictable behavior. Extreme cutout looking effects would not randomly occur.

Repro Rate:
Repro tends to occur within 2-10 minutes of regular height map based painting usage

Note:
- Unnable to reproduce this on Direct3D11 (Attempted for 1 hour)
- Unnable to reproduce this with Terrain Tools Package Uninstalled (Attempted for 30 minutes)
- Unnable to verify if it's a regression or not as Painting on Terrain is unusable with Terrain Tools in v3.0.1 due to https://fogbugz.unity3d.com/f/cases/1252347/