If users edit and change the quantity when billing a purchase order, they might encounter this error due to the following reasons:
1. 'Bill in Advance of Receipt' preference is disabled. Go to Setup > Accounting > Accounting Preferences > Order Management tab and enable this preference.
2. If the 'Bill in Advance of Receipt' is already enabled, remove the Inventory Detail column on the vendor bill form. To do this, follow the steps below:
a. Navigate to Setup > Customization> Transaction Forms
b. Edit the preferred Vendor Bill
c. Under Sublist Fields sub-tab, look for Inventory Detail.
d. Unmark the Show box