Ender Chests dropping chest + 8 obsidian

When mining an ender Chest with a diamond silk touch enchanted pickaxe, the chest drops both the Ender Chest as well as 8 obsidian blocks. Happens every time during my current session. Some people might not complain, but probably should be looked into anyway. Consistently happens even after quitting and saving from session / exiting application. Behaviour appears to have stated after the 1.2.3.6 update. Did not happen prior to this release.