Transform sales order with Inventory Detail Subrecord to fulfillment via scripting

I've run into a problem with fulfilling orders where the lot/serial numbers have been selected on the sales order. 
The problem happens when there is less than 2X the available inventory of that inventory number.  For example: I have 8 left of a lot numbered item.  The sales order is for all 8 of them with the lot number selected on the SO.  I get the error "Invalid issueinventorynumber reference key XXX."  However, when the order is for 4 or fewer of that item, there is no error. 

NetSuite seems to be putting the 8 committed items of that lot on hold so when I try to specify the inventory details of the fulfillment there is not enough inventory to fulfill 8 since only 0 are available.  It's not smart enough to notice that the 8 lot items are committed to THIS order.