Inventory with quantity ZERO or negative

Hello everyone,
we are experiencing this issue: when a technician is executing an activity and he perfoms an installation of an inventory at the customer site, the system perform the "Install" by adding in the Inventory Pool "Installed" the inventory with the desired installation quantity. But, if a technician install all the quantity available, in the resource inventory pool the inventory that we have just installed remains available with ZERO as quantity. The expected behaviour would be that the record, in the resource inventory pool, should disappear.
In addition, this inventory record with ZERO quantity is still available for installation and can go with quantity < 0.