Dynamics AX 2012 - 为什么批处理作业中的某些任务使用空批处理组

I have a question with regards to batch processing in Microsoft Dynamics AX 2012. I have created a Recalculate stock batch job and assigned it to a batch group. However, when I looked at the tasks inside the batch job, I noticed that some of these tasks were NOT using the batch group I assigned but the empty batch group. Why is this please?I have a question with regards to batch process