After completing Meridia's quest I noticed that I had 2 Dawnbreakers in my inventory. When I killed Malkoran in the last room of the dungeon, one of my spells knocked the sword out of the pedastal. So picked up the sword from the ground then activated the shrine which I think gave me the second one. Anyone else seen this happen? This was done on PS3.

yeah read about it, its a explout/cletch with the game consider yourself lucky I wouldnt mind wielding two of them with the effects and the 102 damage I have manage to swith my to

Known glitch, apparently one of her opening spells will frequently do it, just need to save prior incase she knocks it out of the game world.