Location Disappears when Saving a Transaction Dated Prior the Multi-Location Feature was Enabled and Inventory Items were Distributed

After Multi-Location Inventory (MLI) Feature is enabled, the Location field on inventory-affecting transactions becomes mandatory. If user attempts to save an inventory-affecting transaction and dates it before the MLI feature was enabled and inventory items were distributed, the location disappears. This happens because all pre-MLI inventory items are considered to be in a Null location. 

What user must do is to save the transaction after the item was distributed.