GOP: Cumulative availability not correct

Summary:

We are doing a GOP simulation inquiry and when we do a GOP check for 5 pieces with request date as 10-dec-21 (current date is 9-Dec-21) , GOP is asking us to make the item and promising at lead time(11-Dec-21) . However please see the table below for availability .On 12/9 the net available is 38 but the table is showing a cumulative of 0 from 12/9 until 12/14 even though it is calculating the cumulative on 12/15 is (38+19)=57. So it is adding that 38 to the bucket of 12/15. Why is GOP not showing cumulative of 38 in