I don't know how, but I have a Bound Axe permanently in my inventory. I used the spell to create it, as normal, although I may have accidentally cast it twice or something--I seem to remember something weird like that happening before this axe refused to go away.

Not to look a gift horse in the mouth, but has this happened to anyone else?

You probably repaired it while the spell was still active. This happens to almost everyone and Bound Weapons. Don't worry about it unless you want to get rid of your permanent Bound Axe.

the weapon probably got damaged and you fixed it. only way i see this happening by accident. Or the spell you made accidentally had another bound weapon affect on it.

EDIT: ninja

That would be likely. I'm a habitual repairer. If only I was like that around the house, the wife would appreciate me more....

It happend to me with a bound longsword twice im not really worryed about it though cause they dont weigh anything.

Player->RemoveItem "bound_battle_axe" 1
that should do the trick, I had the same problem with a bound bow and spent over an hour trying to fix it.