Internally batching happens based somewhat on renderer setting. In this situation you have two cubes that are light mapped and a ball that is rendered using probes for it's global illumination. Internally the render loop will look at this and batch the cubes together before looking at the sphere and realising that it needs to use a different configuration.
Internally this activates a new keyword causing the batch break. The frame debugger only shows keywords as used by the shader and in this case there are no keywords. Essentially the global keyword state has changed between these calls.
This is intentional as we try to batch lightmapped objects that share a lightmap together and then probe GI objects together. If there was actual other objects that used probe lighting they would be batched with this ball.