Open Directory issue with MS-CHAPv2 via VPN – could be a bug?

Greetings, We use an OD server (10.5.4) to authenticate two other 10.5.4 servers running the stock VPN. Each provides access to separate portions of the internal net. It has worked flawlessly for months, but this weekend, both vpns stopped authenticating users. There were no errors in the OD logs, except for this repeating message in /var/log/system.log any time someone tried to connect: Jul 28 09:23:45 (hostname) /usr/sbin/PasswordService[54]: wrong-sized secret 32 Jul 28 09:23:45 (hostname) /usr/sbin/PasswordService[54]: Unexpected State Reached in MS-CHAPv2 plugin The second we re-entered a user's password in WGM in OD, they could log in again via VPN. We also authenticate users via OD for Kerio mail (Kerberos), and this worked fine throughout the problem. So it seems to be an issue on the OD server, related specifically to authenticating via MS-CHAPv2, or even more specifically, MS-CHAPv2 with the stock VPN server. Thanks for any help you can provide.