Dragging an item out of schedule does not actually remove item from schedule

If you drag an item into the schedule, then realize it's the wrong room and drag the item out of the schedule back to the unscheduled items list it seems to work. If you then refresh however there is no way to now move that session.

On further inspection the session remembers the schedule I have attached two images.
1 shows the "empty" timeslot
2 shows the item still in the scheduled room for the "empty" timeslot