Until GHS-5120 and GHS-5386 can be fixed, subtasks can easily become orphaned if you have a workflow like I describe in GHS-5120 (which is very close to Atlassian's JIRA workflow).

Because of these bugs, I have made my Agile Board filters exclude subtasks with issuetype in standardIssueTypes(). I didn't expect that on the Detail View's Subtasks tab they would be hidden saying "2 sub-tasks are being filtered by the board's Saved Filter". It doesn't make any sense to me to hide subtasks when trying to get more detail on an issue. A subtask is detail about the issue just like description, comments, etc.

To me, I feel all subtasks should always be shown in that tab, regardless of if they are visible in a column on the Agile Board.