The reason appeared to be the first part of the command
"gunzip -c ... | ( tar -xf - ) && touch ..."
which exited with non-zero exit status (141) and "touch ..." was not called.
Running the command manually has showed that gunzip was complaining about
broken pipe (however the archive was extracted successfully).
The attached patch has fixed the problem however I don't feel it is the
The problem seems to be in that specific archive but I'm not sure...
~> uname -a
FreeBSD wep4035 8.0-CURRENT FreeBSD 8.0-CURRENT #0: Tue May 5 00:16:39 CEST 2009 root@wep4035:/usr/obj/usr/src/sys/GENERIC amd64