Was going to fight the necromancer, and one of his shade minions was wielding a dawnbreaker, I picked it up and needless to say the night against all the undead was made relatively easy after that point. However once I finally got rid of my enemies - including the necromancer - quest log told me loot dawn breaker, I walk up to the pedestal and theres no sword in there, I activate it anyway and what do you know, it takes another dawn breaker.

Now I am duel wielding with 2 of the badboys and I wasn't even cheating

LMAO I was going to tell you to DW them, but I see you are already on it. Well played sir

Change the title to "2 Dawnbreakers, awesome!".
You are one lucky man, man.

You looted one of the shades and got a Dawnbreaker?

I've never heard of this bug.

I read this somewhere before. But from what I remember there was some trick to it. But anyways, yup this can happen.