Italian libc it.po file contains only 365 translated messages. Other languages such as German and Czech contain 1200+ messages. I downloaded the sources from http://ftp.gnu.org/gnu/glibc/glibc-2.11.1.tar.xz The po files can be found in the /po directory. The po file revision date is 17/08/2001, it is very old.
Then bring this up with the translators. This is not covered in bugzilla. The translation groups are completely independent.