Steps:

1. Create content item.
2. Schedule publication for the future.
3. Go to Content/Calendar.
4. Go to list view.
5. Select scheduled content.

6a. Click Unschedule and discard scheduling.
Result: Scheduled content is still visible on the list. It disappears after refreshing page or changing view to calendar view.

6b. Click Reschedule and set new date and time.
Result: Event with new date and time is visible, but the old one is also. It disappears after refreshing page or changing view to calendar view.

6c. Open Filters.
7c. Uncheck Future publication/ Change Modified language.
Result: Additional events visible on the list, see, please : http://g.recordit.co/MsXFr3fwf8.gif