private static PartialAjaxResult parseFormData(String savedFormData, URI savedRequest,
            HttpClient client, ServletContext servletContext) throws IOException, InterruptedException {
        boolean isStateless = true;
        if (!isJSFClientStateSavingMethod(servletContext)) {
            String decodedFormData = URLDecoder.decode(savedFormData, StandardCharsets.UTF_8);
            if (isJSFStatefulForm(decodedFormData)) {
                isStateless = false;
                savedFormData = getJSFNewViewState(savedRequest, client, decodedFormData);
            }
        }
        return noJSFAjaxRequests(savedFormData, isStateless);
    }
flash cookie is preserved here

@param request
@param response
@param path
@param paramValues
support/jakarta-ee/src/main/java/org/apache/shiro/ee/filters/FormResubmitSupport.java