Banners not dropping as item when broken after unloading

The bug

Whenever a banner is placed, then saved, it will not drop itself as an item when broken up return to the area. 

How to reproduce

1. Place a banner

2. Break banner and see it drops as an item

3. Place another banner

4. Save and close world

5. Re-open world

6. Break previously placed banner and see it does not drop as item

This happens with the banners in end cities too - they will not drop as items if you leave the area/close the world and come back to them.