Hello Community,
We are having an issue when attempting to confirm a shipment and receiving the following message:

On the shipment, we are not trying to delete any items, simply clicking the “Confirm Shipment” button and receiving that error. The quantity lines are as follows:

These are serialized items, and all have a serial selected so no unassigned quantities. No duplicate shipments were sitting out there, and the lines are all allocated correctly. The order itself shows the lines as open for shipment and every line is marked “back order allowed”. Has anyone seen this error before?