String and Date workflow variables are not recorded in the audit trail

      Map<String, Serializable> map = //
                    ((Map<String, Serializable>) value).entrySet()
                                                       .stream()
                                                       // keep primitive values
                                                       // blobs can be in WorkflowVariables for instance
                                                       .filter(entry -> entry.getValue() != null
                                                               && ClassUtils.isPrimitiveOrWrapper(
                                                                       entry.getValue().getClass()))
                                                       .collect(Collectors.toMap(Entry::getKey, Entry::getValue));