Steps to repro:

1. Open Unity;
2. Create new project;
3. Import attached package and open 'test' scene;
4. Go to PlayerSettings (Edit ->Project Settings -> Player);
5. Expand 'Other Settings' tab;
6. Disable 'Dynamic Batching' checkbox by ckicking on it;
7. Launch the scene;
8. Open Frame Debugger (Windows -> Frame Debugger);
9. Click Enable button;
10. Expand Drawing -> Render.OpaqueGeometry -> RenderForward.RenderLoopJob dropdown list;
11. Observe the draw calls.

Actual result:
Dynamic draw call is shown for SpeedTree billboards (see attached actual.png screenshot).

Expected result:
All SpeedTree billboards should be rendered separately with one draw call each if Dynamic batching is disabled.

Notes:
- Reproducible in 5.5.0b5, 5.4.1p2, 5.4.0f3, 5.3.6p2;
- Reproducible on OSX 10.11.6;
- Not reproducible for SpeedTree meshes;
- Not reproducible for simple gameobjects (Cubes, Spheres).