If you select a piece of equipment from one of the 3 menus (Melee, ranged, curio), if you then change which menu you are in and select an item in the new menu that is in the same position as the item you previously had selected, it doesn’t update the selected item.
To recreate:
Talk to Hadron > Click Entreat Hadron > Select the very first item in the melee menu > Click on the ranged weapon to change menu > now try to select the very first item in the ranged menu. You should find that the preview on the right is still the melee weapon.
Selecting any other item and then the first item fixes the issue.