Box projection on reflection probe breaks batching

When box projection is enabled on a reflection probe in a scene with Shapes objects they are unable to batch because "Objects are affected by different reflection probes." I've just put 4 discs in a scene with a reflection probe to test it. Is this due to a setting I've missed somewhere? I saw in another post that you turned off light probes and reflection probes for the base meshes, but it seems to still to want to use them when box projection is enabled on the probe. Thanks!