Bug in server's export -- List of security flavors

[Tom Haynes <tdh-8AdZ+HgO7noAvxtiuMwx3w@public.gmane.org>]

[tdh@adept tournament]> exportfs -rva
exporting 192.168.2.0/255.255.255.0:/home
exporting *:/
exportfs: could not open /var/lib/nfs/etab for locking
exportfs: can't lock /var/lib/nfs/etab for writing
[tdh@adept tournament]> more /etc/exports
/ *(sync)
/home 
192.168.2.0/255.255.255.0(rw,async,no_subtree_check,insecure,no_root_squash)
[tdh@adept tournament]> uname -a
Linux adept.internal.excfb.com 2.6.29.4-167.fc11.i586 #1 SMP Wed May 27 
17:14:37 EDT 2009 i686 i686 i386 GNU/Linux

So, adept:/home is exported in a fairly typical way that I've had going for
the past 3 years.

[root@witch ~]> mount -o vers=3 adept:/home /mnt
nfs mount: security mode does not match the server exporting adept:/home

The server is not sending any authentication flavors:

MOUNT:----- NFS MOUNT -----
MOUNT:
MOUNT:Proc = 1 (Add mount entry)
MOUNT:Status = 0 (OK)
MOUNT:File handle = [DADF]
MOUNT: 01000700010005000000000053CF6DE4FF1C4572BB2950392EB6993C
MOUNT:Authentication flavor =
MOUNT:

And yet this mount will work from a Linux box:

root@slayer:~# uname -a
Linux slayer 2.6.28-13-generic #45-Ubuntu SMP Tue Jun 30 19:49:51 UTC 
2009 i686 GNU/Linux
root@slayer:~# mount -o vers=3 adept:/home /mnt

I'm guessing that the Linux client is ignoring the list and trying the 
default AUTH_SYS anyway. Is that
also a bug on the client, using a flavor not advertised by the server?