If the inventory is full and get that loot screen, if you equip an item from the loot tab it will change the quality of the item to whatever the quality of the looted item is. So if you have a common shield, and equip an epic shield out of the loot screen that pops up when your inventory is full, it will make your equip common shield into an epic shield. Changes the statistics , but not the name of item. IDK if this is a known issue or not, I'm not a forum guy.