Minecraft wiki entry for Development_versions, associated text: MC-134966 – Using /setblock to place an "Always Active" command block with a command won't execute the command immediately
MC-134967 – NullPointerException when placing Wither Skeleton Skulls.
MC-134974 – Entities in your world can randomly freeze
MC-134982 – Exception when placing a command block.
MC-134987 – Renaming a world doesn't update its name until re-entering the world list.
MC-134988 – Optimizing a world doesn't update it until re-entering the world list.
MC-135039 – The game crashes when /setblock-ing a spawner with an entity ID containing capital letters
MC-135053 – Sticky pistons get stuck when receiving a 0 gametick pulse.
MC-135136 – Crash when placing a chain command block with set command.
MC-135147 – Loading/saving structures with command blocks in them causes errors
MC-135172 – Under certain conditions pistons can't be powered for the first 2 gameticks after being moved.
MC-135185 – All redstone components can become stuck in a powered state when indirectly unpowered.
MC-135186 – Pistons can only be re-pulsed 5 or more gameticks later.
MC-135194 – Pistons react 1 gametick too late.
MC-135229 – Game crash when opening Furnace
MC-135268 – Switching to spectator mode and back creates ghost player duplicates for other players
MC-135293 – Profiler doesn't exit section when an entity is removed, causing recursive profiling and lag