Drag-and-drop issues between parents/epics when not in "Sort by Rank" mode

[Ryan]

Situation

I like to Sort by Due Date instead of by Rank (Default) when using Advanced Roadmaps. I also like to use Roadmaps to keep projects tidy and ensure I move any floating tasks (issues without parent) into the correct epics or parents.

Expected Behaviour

When sorted by Due Date:

1. I should be able to drag-and-drop a task to a new parent, either between parents or from the "issues without parent" section
2. Using drag-and-drop within the same parent shouldn't do anything since the order is determined by Due Date field.

Actual Behaviour

1. There's a complete lock on all drag-and-drop behaviour if sorted by anything other than Rank, so if I sort by Due Date I can't drag issues to be underneath a different parent (but I can with Rank sort)
2. As expected

Workarounds

1. Sort by Rank, clean up the tasks into correct parents, then sort by Due Date again if needed
2. Use bulk change method to add a parent
3. Open the task and use the Epic Link field

Is this a bug or a known limitation?