No breaking animation when doors attacked by mobs

When zombies break down doors, the doors are missing the breaking animation telling the player how soon the door will break. In Screenshot_2015-10-05-23-18-27.png those zombies had been banging on that door for several seconds before taking the picture. No breaking animations appeared.

Tested and confirmed on creative and survival with Samsung Galaxy S4 android 5.0.1 MCPE 0.12.1.