odd inconsistency with nfs

I'm having an interesting/odd problem with nfs (I think). We recently
(Monday/Tuesday) upgraded our file server from an ancient redhat 7.3
system to a shiny new centos 6.4 system. We don't see any issues between
the other centos boxes, but things get a bit weird when we start
mounting on the old solaris clients.

The initial symptom was that the 'tab complete' wasn't working, and then
we noticed that typing 'ls *' in the mounted directory was bombing. I
tried forcing the mounting back to nfs3 but it's not consistent. I've
set up two boxes as servers and one of the solaris boxes is my client.
Each server has two shares that are mounted on the client. Of those
four, one of them works properly and the other three do not. I've spent
most of the day trying to debug this and I cannot for the life of me
tell why one share works and the rest don't. Nothing seems to be special
about that share versus the rest.

Here are notes on how things are set up.

on duke: (nis server)
vi /etc/ypfiles/automap
scrs1_bolt -soft,intr,retrans=1 boltzmann:/scrs1_bolt
summit_bolt -soft,intr,retrans=1 boltzmann:/summit_bolt
scrs1.mirror -soft,intr,retrans=1 goblin:/scrs1.mirror
summit.mirror -soft,intr,retrans=1 goblin:/summit.mirror
( cd /var/yp ; make )

on boltzmann: (nfs server)
df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sdb2 50G 13G 37G 26% /
tmpfs 3.9G 1.2M 3.9G 1% /dev/shm
/dev/sdb3 177G 188M 175G 1% /aux
/dev/sda3 208G 44G 164G 21% /aux2
mkdir /aux/scrs1_bolt
mkdir /aux2/summit_bolt
ln -s /aux/scrs1_bolt /scrs1_bolt
ln -s /aux2/summit_bolt /summit_bolt
chmod 777 /aux/scrs1_bolt /aux2/summit_bolt
service nfs restart
vi /etc/exports
/scrs1_bolt xxx.xxx.xxx.0/24(rw,no_root_squash,sync,insecure)
/summit_bolt xxx.xxx.xxx.0/24(rw,no_root_squash,sync,insecure)
exportfs -rv

on bigdog: (client)
mkdir /tmp/test/b1 /tmp/test/b2 /tmp/test/g1 /tmp/test/g2
touch /tmp/test/b1/nothing_is_mounted
/tmp/test/b2/nothing_is_mounted /tmp/test/g1/nothing_is_mounted
/tmp/test/g2/nothing_is_mounted
mount -F nfs -o nfsvers=3 boltzmann:/summit_bolt /tmp/test/b1
mount -F nfs -o nfsvers=3 boltzmann:/scrs1_bolt /tmp/test/b2
mount -F nfs -o nfsvers=3 goblin:/summit.mirror /tmp/test/g1
mount -F nfs -o nfsvers=3 goblin:/scrs1.mirror /tmp/test/g2
ls -l /tmp/test/*
-rw-r--r-- 1 root other 0 Jul 3 14:39
/tmp/test/nothing_is_mounted

/tmp/test/b1:
total 24
-rw-r--r-- 1 root other 0 Jul 3 12:32 SUMMIT_BOLT
-rw-r--r-- 1 root other 0 Jul 3 09:26
boltzmann_test_summit

/tmp/test/b2:
total 32
-rw-r--r-- 1 root other 0 Jul 3 12:31 SCRS1_BOLT
-rw-r--r-- 1 root other 0 Jul 3 09:26
boltzmann_test_scrs1

/tmp/test/g1:
total 280
-rw-r--r-- 1 root other 0 Jul 3 15:40
.00_summit_nas_volume
-rw-rw-r-- 1 root other 0 Jul 3 15:03
SUMMIT_MIRROR

/tmp/test/g2:
total 120
-rw-r--r-- 1 root other 0 Jul 3 15:40
.00_scrs1_nas_volume
-rw-rw-r-- 1 root other 0 Jul 3 15:02 SCRS1_MIRROR

ls -la /tmp/test/b1/*
-rw-r--r-- 1 root other 0 Jul 3 12:32
/tmp/test/b1/SUMMIT_BOLT
-rw-r--r-- 1 root other 0 Jul 3 09:26
/tmp/test/b1/boltzmann_test_summit

ls -l /tmp/test/b2/*
ls: No match.

ls -l /tmp/test/g1/*
ls: No match.

ls -l /tmp/test/g2/*
ls: No match.

mount
/tmp/test/b1 on boltzmann:/summit_bolt read/write/remote on
Wed Jul 3 15:41:11 2013
/tmp/test/b2 on boltzmann:/scrs1_bolt read/write/remote on Wed
Jul 3 15:41:11 2013
/tmp/test/g1 on goblin:/summit.mirror read/write/remote on Wed
Jul 3 15:41:11 2013
/tmp/test/g2 on goblin:/scrs1.mirror read/write/remote on Wed
Jul 3 15:41:11 2013

umount -a /tmp/test/b1 /tmp/test/b2 /tmp/test/g1 /tmp/test/g2

If I use automount to access the shares on the client, the mounts are
made by default with nfs4 and we see this same 'no match' behaviour.
It's probably something really stupid but I'm just not seeing it...

If anyone has ideas and/or needs more info, please let me know.