On my fully updated FC6 systems recently I've been seeing lots of "Unable to
change GID to 455 temporarily" errors in the logs, e.g.:
Dec 21 23:55:44 marimba sshd[7580]: pam_keyinit(sshd:session): Unable to change
GID to 455 temporarily

(455 is a valid GID on our systems.) I haven't personally noticed any problems
logging in to these systems, but some users have reported that they can't open
sftp sessions any more.

May perhaps be related to bug # 212329?

This is using pam-0.99.6.2-3.fc6, openssh-4.3p2-14.fc6, on both i386 and x86_64
systems.

How reproducible: uncertain - seems to be about 10% of all ssh connections from
looking at /var/log/secure.

Steps to Reproduce:
1. Try to sftp to affected system.
  
Actual results:
Password auth appears to fail, "unable to change GID" error is logged in
/var/log/secure


Expected results:
sftp session is opened.