When you have a full hot bar, have a pair of sheers in your hotbar. Have the sheers selected and then use the pick block click on a bunch of blocks/items (That are not in your hot bar) and the sheers will not be replaced, and will become duplicated sometimes.

Edit: If tool replacement with pick-block key is not intended, I also tried doing the same with an enchanted diamond shovel and it was replaced. These duplicated sheers also appear to be ghost items.