Well, there seems to be more than one, but this is only about the one that hurts me at work the most. Regardless of the type of smartcard used to login, the new RDP client refuses to present a PIN login, instead prompting for a username and password. Now, if you’re accounts are setup to require smartcard login, then your password is randomized, so users cannot possibly know it. So, no login over RDP, which really puts damper on accessing Terminal Server apps.
The solution we used for now is to uninstall the update (KB 925876) – Control Panel, Add/Remove Programs (Show Updates checked). No reboot needed.
The link I found this at has more info on issues others have had:
Backing down to the previous version fixed the issue, and smartcard logins were cleanly passed through the RDP client again. For now, we have blocked the update on our WSUS server.
Hope this helps!