A few years ago we planted what we thought were smoke bushes.They grow very nicely and are quite attractive all season. But late in the fall, they completely die and eventually roll away like a tumbleweed, only to sprout up again in the spring from the ground. No one thinks this is normal for a smoke bush.
You are correct. That does not sound normal for a smoke bush. Take a few clear pictures of the bush as it grows this season and a cutting of a branch with well developed leaves, and a flower to your local County Cooperative Extension Office for identification.