See comments.
I reproduced this very quickly using the following steps.
First start a script which looks like this:
while [ 1 ]
do
prtpicl -v
done
Then in another window. Start repeatedly executing prtpicl -v and then
control-C the prtpicl when it is in the process of displaying the
physical-platform portion of the tree. Keep trying it a few times and
eventually the prtpicl in the while loop will start reporting <ERROR:
Property value unavailable> for every single value under the
physical-platform. This behavior persists until I manually reset the
picl daemon with svcadm restart picl.
Matt