ZFS Snapshots Not able to be accessed under .zfs/snapshot/name

[dweimer]

I have a few systems running on ZFS with a backup script that creates 
snapshots, then  backs up the .zfs/snapshot/name directory to make sure 
open files are not missed.  This has been working great but all of the 
sudden one of my systems has stopped working.  It takes the snapshots 
fine, zfs list -t spnapshot shows the snapshots, but if you do an ls 
command, on the .zfs/snapshot/ directory it returns not a directory.

part of the zfs list output:

NAME                        USED  AVAIL  REFER  MOUNTPOINT
zroot                      4.48G  29.7G    31K  none
zroot/ROOT                 2.92G  29.7G    31K  none
zroot/ROOT/91p5-20130812   2.92G  29.7G  2.92G  legacy
zroot/home                  144K  29.7G   122K  /home

part of the zfs list -t snapshot output:

NAME                                            USED  AVAIL  REFER  
MOUNTPOINT
zroot/ROOT/91p5-20130812 at 91p5-20130812--bsnap   340K      -  2.92G  -
zroot/home at home--bsnap                           22K      -   122K  -

ls /.zfs/snapshot/91p5-20130812--bsnap/
Does work at the right now, since the last reboot, but wasn't always 
working, this is my boot environment.

if I do ls /home/.zfs/snapshot/, result is:
ls: /home/.zfs/snapshot/: Not a directory

if I do ls /home/.zfs, result is:
ls: snapshot: Bad file descriptor
shares

I have tried zpool scrub zroot, no errors were found, if I reboot the 
system I can get one good backup, then I start having problems.  Anyone 
else ever ran into this, any suggestions as to a fix?

System is running FreeBSD 9.1-RELEASE-p5 #1 r253764: Mon Jul 29 15:07:35 
CDT 2013, zpool is running version 28, zfs is running version 5

-- 
Thanks,
    Dean E. Weimer
    http://www.dweimer.net/