Welcome to the Centrify Express forums.
Can you please let us know what's the current version of OpenSSH you're using on the system exhibiting the problem?
(which sshd)
What is the version of Centrify Express?
(adinfo -v)
Finally, remember that you don't need to install Centrify-enhanced OpenSSH.
See this thread for a similar exchange: http://community.centrify.com/t5/Centrify-Express/Using-publickey-authentication-for-ssh/td-p/21412
Robertson