Block damage is reset when stack count changes.

A new feature was added to prevent players from cheating durability of their tools. When the itemstack in hand changes, block damage is reset. However, this also resets block damage when the itemstack count changes. So if you're breaking any hand-breakable block with drops, and holding an incomplete stack of such drops, each time you collect the drop from the previous block you will be interrupted in breaking the current block. This is very annoying.