2.2.0 setting temporary mountpoint does not work

Trying to change temporarily the mountpoint of "Music" of my 1.9.4 pool so it does not collide with the one of the 2.2.0 pool with "zfs mount -o mountpoint=/Users/arne/Music194 zfs-extern".
But it does not change the mountpoint.
It stays in the mountpoint as given when the pool is imported ("/Users/arne/Music").
I can only change it permanent with "zfs set mountpoint= ...".
But it does not change the mountpoint.
It stays in the mountpoint as given when the pool is imported ("/Users/arne/Music").
I can only change it permanent with "zfs set mountpoint= ...".