Product: NetSuite 2020.1
Navigate to Transaction > Demand Planning > Generate Item Supply Plan > Open generated Item Supply Plan > hover to More > Open linked Gross Requirements Inquiry
Linked Gross Requirements Inquiry has first line "Planned Work Order - Component Consumption" with negative quantity
This happens when the item is a component of an Assembly on which the demand date for the Assembly is prior to the set start date of the Item Supply Plan.
It is noted as well in SuiteAnswers article 28016 that NetSuite will not consider recommended work order demand for orders with a production start date that is before the planning start date.
To get around this:
1. You may extend the start date of your Item Supply Plan to include the demand date of the Assembly
2. Set a future demand date (Expected Ship date if Sales Order / Production Date if Work Order) in the sales order/work order taking into consideration the lead time to build the Assembly item and it's components.