I saw the release note.
'Batch edit due dates in course content' function will be updated by 6th December.
so I tested it in hanyang-test.blackboard.com
Example. after current start date transfers 1/8/18 to 9/10/18, automatically due date change 1/8/18 to 9/10/18.
I think you have to make language matched.
current start date = due date
|Product Version (if applicable):||1|