Get historic task instances filtered by candidate group

Flowable Engine
1

I’m trying to get all historic task instances filtered by candidate group but i cannot get any result.
The same request for runtime task instance is working.
After digging in database, i can see that ACT_HI_IDENTITYLINK is never populated while ACT_RU_IDENTITYLINK is.
Do you know when historic identity link is supposed to be populated ?

I used this method for getting historic task instances (no result) :

List<HistoricTaskInstance> hrTasks = cmmnHistoryService.createHistoricTaskInstanceQuery()
            .taskCandidateGroupIn(Arrays.asList("group1","group2"))
            .caseInstanceId(caseInstanceId)
            .list();

And this one for getting task instances (one result) :

    List<Task> tasks = cmmnTaskService.createTaskQuery()
            .taskCandidateGroupIn(Arrays.asList("group1","group2"))
            .caseInstanceId(caseInstanceId)
            .list();

Thank you