Duplicate deliveries creation for single PO line in Batch Job

Hello Experts,

I have the VL10G batch job running for every 15 mnts for creating deliveries for POs. Recently for some reason, i see duplicate deliveries being created for same PO line for single quantity. Suppose, i have a PO line with 10 quantity, when I checked the PO history, i see two different delivery notes created for the same 10 qty in each. I assume that there could be some buffering delays in Batch job or the PO being edited during batch run. But I can not come a conclusion on this issue. Please share your ideas.

Thanks in advance.