Well, it seems it was related to the nfs mount for “/home” in /etc/fstab
I restructured to use a bind mount from the root nfs mountpoint and put
the following clause in nfsmounts.conf
# Would cause all mount to /export/home would be done in
# the background
[ MountPoint "/export/home" ]
background=True
Booting up to the graphical login screen takes a few moments longer, but it seems stable enough [at least for now].