Reproduction steps:
1. Open the attached project LightProbeAnchorBug.zip
2. Open the DrawCall scene
3. Enter Play mode
4. Open the Frame Debugger window
5. Press space to switch between examples A and B
6. Observe in Frame Debugger window for each of examples.
7. Observe that the example A has three independent probes with assigned child-objects and none of them are batched.
8. Observe that the example B has the only one probe with three assigned child-objects and all mesh renderers are batched correctly.

Expected results: all mesh renderers will be dynamically batched.
Actual results: mesh renderer does not batch even if they share the same light probe.

Reproduced with 5.4.0f3, 5.4.1f1 and 5.5.0b4.
Not reproduced with 5.3.5p6, 5.2.3p2 because of the errors in the console.

Workaround (Example B):
Three gameObjects are attached to one parental object and are batching dynamically as they should be batched.

By Design: the behavior could be explained by the render sort ordering. You can see the rendering order by disabling "dynamic batching" in player settings and have a look at rendering order in the frame debugger.