diff --git a/jbpm/jbpm-usertask/src/main/java/org/kie/kogito/usertask/impl/InMemoryUserTaskInstances.java b/jbpm/jbpm-usertask/src/main/java/org/kie/kogito/usertask/impl/InMemoryUserTaskInstances.java
index 55da7c4c0e2..def2088da39 100644
--- a/jbpm/jbpm-usertask/src/main/java/org/kie/kogito/usertask/impl/InMemoryUserTaskInstances.java
+++ b/jbpm/jbpm-usertask/src/main/java/org/kie/kogito/usertask/impl/InMemoryUserTaskInstances.java
@@ -70,7 +70,7 @@ public void setDisconnectUserTaskInstance(Function<UserTaskInstance, UserTaskIns
     public Optional<UserTaskInstance> findById(String userTaskInstanceId) {
         try {
             if (!userTaskInstances.containsKey(userTaskInstanceId)) {
-                return null;
+                return Optional.empty();
             }
             UserTaskInstance userTaskInstance = mapper.readValue(userTaskInstances.get(userTaskInstanceId), DefaultUserTaskInstance.class);
             return Optional.ofNullable(reconnectUserTaskInstance.apply(userTaskInstance));