Board Thread:General Discussion/@comment-1487677-20160805054525/@comment-10301320-20160806040303

That's not a plot hole, that's an oversight. The manga never specifically stated Zanpakuto spirits can't have Zanpakuto. Still clarification on the matter would be nice, but I feel if a being can pour their reiatsu into an Asauchi then it's entirely plausible that they can have a Zanpakuto, and I think (not sure) Zanpakuto have their own reiatsu.