Minecraft wiki entry for Development_versions, associated text: MC-8184 – Redstone block and torches don't power dispensers, droppers, TNT and noteblocks.
MC-8826 – Adding an item to a hopper with a dropper does not change comparator state.
MC-9018 – Faceless furnace/furnace duplication glitches.
MC-9336 – [13w06a] Extending piston animation missing.
MC-9460 – Piston retracting disappears if pushed out by another piston.
MC-9534 – Issues with baby cows' hitboxes.
MC-10500 – Unicode defined font in texture pack is misfunctional.
MC-10670 – Hard crash when trying to load a custom world.
MC-10786 – Comparator doesn't update when a hopper takes in only part of an item stack.