Enable the "Enforce rules on reset" feature
By default in Access Manager 1.2, Password History and minimum password age are not obeyed when using the Password Reset action, this is because it is performed as an administrator level function and when an admin resets an Active Directory password they do not need to obey Password history. You can enable Password History checking for this through the Directory configuration however.
Log into the Administration web portal and navigate to the Directories tab, expand the configuration section of the directory connector and go to the Advanced tab. You should see the option Enforce Rules on Reset, enable this and save the configuration. Now when a user performs a password reset they will also be forced to use one that does not match a previous one used in their password history.