Steps to repro:

1. Open attached project and '04_AutomaticInstancingSubmeshes';
2. Launch the scene;
3. Open Frame Debugger (Window -> Frame Debugger);
4. Expand DepthPass.Job section;
5. Observe draw calls under DepthPass.Job section.

Expected result:
All mesh subsets are batched in DepthPass.

Actual result:
Only first mesh subset is batched with Draw Mesh (instanced) calls. See attached screenshot for clarity.

Notes:
- Reproducible in 2017.1.0b1, 5.6.0f3, 5.5.2p1;
- Reproducible on Windows 10 and OSX 10.12.3;
- Reproducible only when spawning multimesh instances; not reproducible for simple meshes;
- Reproducible only when spawning gameobjects with submeshes; not reproducible when drawing submeshes via DrawMeshInstanced;
- Submesh instancing works correctly in Shadows and Render passes;
- The bug is also reproducible in Standalone player.