Steps to reproduce:
1. Download attached project
2. Open OverrideGeometryTest scene
3. Enter play mode
4. click on Perform OverrideGeometry

Expected results: All all cases just one vertex is modified
Actual results:
Sprite A
On Start - Works as expected
On OverrideGeometry - Works as expected

Sprite B
On Start - Works as expected
On OverrideGeometry – Vert[0] moved down as expected, but all vertices seem to be shifting left with every click

Sprite C
On Start – Verts all shift down a uniform amount, cutting off part of the sprite immediately.
OnOverrideGeometry – works as expected

Sprite D
On Start – All verts shift left a tiny amount
On OverrideGeometry – Vert[0] moved down as expected, all verts shift left with every click

Reproduced with: 2019.3.0a7, 2019.2.0b7, 2019.1.8f1, 2018.4.8f1

Note:
- In build, vertices are correctly overridden (tested in Windows Standalone, iOS)