Legacy Password Policy
passwordMaxFailure doesn't behave as expected by newer LDAP clients. DS doesn't return error LDAP_CONSTRAINT_VIOLATION until after the retry limit is exceeded. Newer clients are expecting the failure to occur when the limit is reached(like in Sun DS/ODSEE), not when it is exceeded. Since this has always been the behavior it is the legacy behavior.
passwordLegacyPolicy: on|off (default is on)
To have the DS send an error when the limit is reached(not when it is exceeded), set this attribute to off