Two different translation keys are built for each Status and Priority (the Products cannot be translated yet, see #10), one for the livetable filter and one for the task document (generated from custom displayer):
TaskManager.TaskManagerClass_status_InProgress=In Progress
TaskManager.StatusClass_status_InProgress
Since the livetable filter translation key follows the XWiki default mechanism, we should update the one from the custom displayer to reuse the existing one.