How to reproduce:
1. Open the attached project "1159573.zip"
2. Create a Cube Prefab Instance in the Scene
3. Enable GPU Instancing on the sprite Material
4. Inspect the Cube instance

Expected result: Cube instance is rendered
Actual result: Cube instance does not render at all or renders incorrectly

Reproducible with: 2017.4.29f1, 2018.4.2f1, 2019.1.7f1, 2019.2.0b6, 2019.3.0a6

Notes:
Console throws an endless stream of warnings: Instancing: Use SpriteColor or SpriteFlip for renderers that are not sprite renderers. Values are undefined.
If GPU instancing is enabled before creating an instance, the Mesh does not render at all.