Some entries on the auto direct map failed to mount

Hi Experts,   I got stuck in a bizarre autofs behaviour by which some entries in auto direct map failed mount. Other servers on the network use the same autofs configuration work properly.

# cat /etc/auto_master
+auto_master_sp
/net            -hosts          -nosuid,nobrowse
/home           auto_home       -nobrowse

# ypcat -k auto_master_sp
/home auto_home_sp       -rw,hard,retry=24,intr,nobrowse
/net -hosts             -nosuid,fstype=cachefs,backfstype=nfs
/- auto_direct_sp       -ro,hard,retry=24,intr

# ypcat -k auto_direct_sp|egrep 'SUNWspro12|tss'
/opt/tss -rw,hard,retry=24,bg,intr      devcnfs11:/export/nfs2/bns/tibco
/bns/gtssunix -rw,hard,retry=24,intr,bg devcnfs11:/export/nfs2/bns/gtssunix