PGP Passphrase not synchronizing with Active Directory

I am working in an environment with Windows 7 computers bound to an Active Directory domain.  We've been using PGP since 2008 and everyone who set their PGP passphrase back then still has that same passphrase no matter how many times they've reset their Active Directory password.  Is there a setting I'm missing that disables this synchronization?  If not, is there a way to force synchronization?

Thanks!