I'm getting this error: "can't have empty value for field Assignee". The field Assignee is left pretty much default: cannot be empty and the assigned bundle is "Assignees". There are two assignees in the list available. The best thing is: the value is NOT empty. An assignee is actually filled in and still the issue reporter complains that it isn't. It gets better: if I uncheck "Can't be empty" in the administration, everything goes well and the assignee is correctly filled in. But I do want this checkbox ticked! What's going on? using YouTrack 3.1.