When I was trying to break an ender chest using an iron pickaxe with only silk touch enchantment and 0 durability (so it breaks with next use) in survival mode, the chest did not drop as an item when it broke. It did not produce any drop at all, not even 8x obsidian.
This bug applies to every block tested so far.
Tile Drops toggle is kept on all the time.

Steps to reproduce:

1. Obtain such a pickaxe with /give @p iron_pickaxe 1 1000
2. Enchant with /enchant @p silk_touch 1
3. Break any block in survival mode, and it would not drop.