Comment 2 for bug 309049

As an update, it turns out that the pool containing the zone filesystems needs a mountpoint for the pool. Setting a mountpoint for syspool allows zone clones (and thus devzone) to work properly:

zfs set mountpoint=/syspool syspool

I'm not sure what the ramifications are for tools like apt-clone or bootadm in this scenario. In any case, this is a better work-around until the real issue with zoneadm is fixed.