How Do I Troubleshoot Inaccurate Quantity On Order Value

I’m working in a NetSuite instance where the Quantity On Order that is displayed on the item master in the “Location” sublist is not accurate for certain items only. The column for “Quantity On Order” is empty, but I have an open, approved Purchase Order in the system. Does anyone have tips for troubleshooting?

I’ve compared different items and can’t find why one is working and the other isn’t. There may be two items on the same PO and one item has a correct value for Quantity on Order and the other item does not. I’ve reviewed the Item Location Configuration records, and they’re identical on the items I’m comparing.