We use a Kanban board with Tasks and Sub-Tasks, with Epics as our swim lanes. This works pretty well. However, during stand-up we filter by Assignee. The way we work, one person can be assigned to a Task, but another person assigned to some of the sub-tasks of that Task. When not filtered, tasks and sub-tasks are correctly displayed in swim lanes according to the Epic that the Task belongs to. But, when the assignee of the sub-task filters to show only their issues, sub-tasks that belong to Tasks that are assigned to other people drop to a swim lane at the bottom labelled "Issues without Epics".
Am I doing something wrong?