[Bug] Adding additional copies to Inventory with Tradelist populated

As I've been adding additional copies to Inventory, I've come across a bug when I already have six (6) or more in inventory, with two (2) or more in the trade column.

When I type the name of a card that is already in Inventory, a new line appears with a quantity of one.  If I have five or less of that card already, everything is fine.

If I already have have six (6) or more in Inventory, with two (2) or more in the tradelist column, when the new row is entered for the card, it automatically populates with one (1) in the Inventory column and (1) in the trade column.  At the same time, it reduces the number of card in the tradelist column of the original (six quantity) row to one (1).

This does not happen if I have five (5) in inventory and one (1) in the tradelist.  When I enter a card that already has those quantities, I get a new row with a one (1) in inventory and zero (0) in the tradelist.