Shields can not be assigned to shield entry in Equipment tab

Hello,

I was trying to equip a buckler for a new character and it does not give the option to assign it to the Shield field in the Equipment tab. This character has a standard shortbow that is marked as carried also. When I try to equip any shield to the Shield field, it will list Not carried, carried and shortbow in the drop down field. If I remove the shortbow from carried, it will not appear on the list for the shield.

This in the Pathfinder RPG Core Supplements data set.