Opening the bingo map and pressing move to offhand displays item in offhand

[SquarePlayn]

• Start a game
• Open the map (right-click it)
• Hover over an item
• Press the 'move to offhand' button (f by default)
• Notice your offhand now displays this item you do not actually have

The item cannot be used and will disappear as soon as you put something else in your offhand, with the original item you had there appearing again, so it seems to be not exploitable, just a visual glitch.