Strange behaviour of getcwd for hidden ZFS snapshots.

Hi,

I was trying to restore some deleted files from a snapshot with rsync:

[/home/www/.zfs/snapshot/zfs-auto-snap_hourly-2015-08-31-12h00/www.tegenbosch28.nl] 

root_at_zfs.digiware.nl# rsync -rav * /tmp
rsync: getcwd(): No such file or directory (2)
rsync error: errors selecting input/output files, dirs (code 3) at 
util.c(1101) [Receiver=3.1.1]
Exit 3

Turns out that if the snapshots are hidden, then getcwd() errors out?
Setting snapdir=visible on the volume gets it to do its job.
As does changing out of the snapshot directory and using the full path 
for source and destination

Is this a bug or a feature?
10.2-STABLE FreeBSD 10.2-STABLE #324 r287170: Thu Aug 27

--WjW