The ESO item dupe bug has been a troublesome concern of many since the past few days. People have been exploiting glitches in the game to benefit in terms of item duplication for quite some time now. In fact it has been so ever since the game was launched officially on April 4, 2014.
What actually happens is that through the ESO item dupe bug in question, people can deposit an item in the Guild Bank and withdraw the item for virtually infinite times. It is as simple as that.