Say Bob the fighter dies heroically while fighting some cultists. His companions realise they are outmatched and decide to run. But first, they quickly cut off one of Bob's fingers and take it with them.
After reaching safety, they cast resurrection on the finger, and it grows into a new Bob, assuming this answer is correct.
Meanwhile, the cult decide not to waste a perfectly good corpse. So they wait until nightfall and cast create undead on it.
Is there anything wrong with this scenario? Could Bob the fighter and his companions return to the cultists to be confronted with Bob the undead?