Planned Orders pegged to Qty Zero SO

We are on 12.1.3 and we are seeing some planned orders whose pegging shows as follows:

Qty 0 Pegged Qty 1 on 12-nov-2013 (sales order 144128)

There is no line# in the sales order information above and the SO line to which this is most liklely pegging to is cancelled.(hence the qty 0).

Would you know why this would happen since ASCP will not see cancelled sales orders and why the planned order is pegging to something with qty 0.We use complete refresh for our collections (with net chnage we kinow there are issues with cancelled orders also getting collected and plannned)

thanks

rahul