@Override
    public void updateAttributes(final Authentication authentication) {
        authenticationDate = authentication.getAuthenticationDate();

        val finalAuthnAttributes = CoreAuthenticationUtils.mergeAttributes(attributes, authentication.getAttributes());
        attributes.clear();
        attributes.putAll(finalAuthnAttributes);

        val finalPrincipalAttributes = CoreAuthenticationUtils.mergeAttributes(principal.getAttributes(), authentication.getPrincipal().getAttributes());
        principal.getAttributes().clear();
        principal.getAttributes().putAll(finalPrincipalAttributes);
    }
Map of handler name to handler authentication failure cause.
core/cas-server-core-authentication-api/src/main/java/org/apereo/cas/authentication/DefaultAuthentication.java