NPE when retrieving a task by work item id (via remote API)

Unable to retrieve a task by work item id (getTaskByWorkItemId)... it returns null and in bpm suite server log I see:

09:52:25,976 INFO [stdout] (http-localhost.localdomain/127.0.0.1:8080-4) JaxbCommandsResponse: unknown result type TaskImpl from command GetTaskByWorkItemIdCommand added.

Looking at [1] it seems like it does not handle the TaskImpl object properly?

Happens on 6.2 and 6.3. It is not possible to map a Task from Node if workitemid is not working.

[1] https://github.com/droolsjbpm/droolsjbpm-integration/blob/master/kie-remote/kie-remote-services/src/main/java/org/kie/remote/services/jaxb/JaxbCommandsResponse.java