Steps to reproduce:

1) Download attached project and open in Unity
2) Switch platform to Android in the Build Settings
3) Make sure Graphics API is set to OpenGLES3/Vulkan in the Player Settings
4) Enable Development build in the Build Settings
5) Build and Run project on a device
6) Connect device to the Frame Debugger
7) Pick a sample(enable)
8) Find RenderForward.RenderLoopJob in the Frame Debugger and you will see that Draw Mesh(instanced) is split into several DrawCalls

Expected result: Instanced mesh should be counted as one because it has the same material
Actual result: Draw Mesh(instanced) is split into several DrawCalls because of warnings: (check attached image "actual.png")
"Objects have different materials"
"Render different meshes or submeshes with GPU instancing"
Note: All spheres are exactly the same and share same material

Reproduced with:
5.6.4p4, 2017.1.2p3, 2017.2.0p4, 2017.3.0f, 2018.1.0a7

Devices under testing:
[0143] Samsung Galaxy S8, GPU: Mali-G71
[000037] iPad Mini 2 9.3.1

Did not reproduced using Win Standalone build