Heh, I hadn't seen one of these yet, so I grabbed screenshots: I'm not dragging that Shielding Token: I'm dragging the table beneath it. So what happened is that I clicked to open the quest loot chest and then immediately decided I wanted to scroll the table. I went to drag the table, but I clicked exactly where the falling Shielding Token was coming into view. I then released really really quickly. (It probably wasn't through with the falling animation.) The item was then mislocated, resting in the wrong place on the screen. I could drag the table around beneath it as you see. Picking up the item and releasing it in place caused the system to recognize "oops, items aren't allowed to be out there" and snap it back into the chest.
I've seen bug reports about magical floating items, like this method of forcing it to happen (which was subsequently fixed). But this was the only time I'd seen it happen myself, whatever the cause, and I can't remember if THIS method had been posted before. So I posted just in case it were helpful.