Make sure that time is in sync.
Run ndsrepair -T to check this.

Check your NTP settings as well.

From iMonitor:

The time synchronization used by eDirectory is not synchronized between
the source and target servers.

On 29/05/2012 13:46, dschaldenovell wrote:
> Started seeing this after the Memorial Day Holiday
> (Error -659) Time synchronization services has detected a problem with
> an operation attempting to modify replica information.
> An error occured writing the changes to NDS. Some data may not have
> been written.
> This was seen by our Help Desk when they tried to reset an account from
> the Intruder Lockout condition. Further it seems to be happening with
> attempting to change passwords as well.
> Any ideas?