Sunder Question

[Sithobi1]

If the weapon is broken, any magic on it is lost, including the curse.

 

[Dross]

If the weapon is broken, any magic on it is lost, including the curse.

The way I see it is this:
The curse is "cast" on the victim and does not actually reside IN the weapon. The curse is similar to a spell that is on the victim. The original caster is gone, but not the effect.

Being broken should mean that the cursed weapon cannot curse anyone else, but the effect of that curse is still in place.