Using Probuilders Triangulate on a Polybrush mesh causes the mesh to become invisible and throws loads of errors

To reproduce:
1. Create a new project
2. Using ProBuilder create a shape (cube works)
3. Using PolyBrush modify the shape
4. Click triangulate in ProBuilder
5. Mouse over the mesh/modify it with PolyBrush
Expected result: Modifications happen, or if that is not possible gracefully fails and informs the user
Actual result: At first, errors are thrown, then the mesh disappears completely

Reproduced with: Polybrush 1.0.0, ProBuilder 4.1.0 on Unity 2019.3.0a10, 2018.4.1f1

Note: Gif attached