I am sure I do not need to describe this glitch to anyone who has played mortal for any amount of time. In a nutshell, slots in your bank become glitched out (seems to be the top row mostly). Putting an item on one of these glitched out slots results in it being instead moved to the first available slot in your bank and then the slot you tried to put it in becomes an invisible item and is oddly tethered to the original item. Hovering your mouse on this invisible item results in the tool tip of the item being shown and click dragging or right clicking affects the original item as if it is located in both slots simultaneously.
Hope that explains it, but if more explanation is needed just ask.
Hope that explains it, but if more explanation is needed just ask.