To reproduce:

1. Download attached project "OpaqueOrderTest5.4.2f2.zip" and open in Unity 5.4.2f2
2. Open "test" Scene
3. Enter to Play mode
4. Enable Frame Debugger
Note: Observe that Static batch is not rendered first
4. Download attached project "OpaqueOrderTest5.6.1p2.zip" and open in Unity 5.6.1p2
5. Open "test" Scene
6. Enter to Play mode
7. Enable Frame Debugger
Note: Observe that Static batch is rendered first

Note: There is discussion about this issue: https://forum.unity3d.com/threads/opaque-order-causes-overdraw.476709/
Note: This issue appears both on Windows and OSX.

Reproduced on Unity 5.5.0f1, 5.6.2p1, 2017.1.0f2 and 2017.2.0b1
Not reproduced on Unity 5.4.5p4
Regression on Unity 5.5.0f1
Could not check for regression on Unity 5.5 Alfa and Beta because Frame Debugger does not show Static Batch