Block models that need an IModelData are not rendered correctly in the book because you call the non IModelData aware version of BlockRendererDispatcher.renderModel() with in turn call the IModelData aware version passing in an empty IModelData

You should probably add a way to supply an IModelData for each block position in the template when we create it

This issue is stale because it has been open for a while with no activity. Please bump if this is still an issue, or this ticket will be closed soon.