Minecraft 16w32a, Minecraft 16w32b, Minecraft 16w33a
related to the fix of
hoppers are running on a global timer now, which apparantly only allows them to transfer items every 4gt. This breaks countless redstone contraptions, that rely on precise timings.
Example: classic dropper-hopper monostable (see picture), a widely used component in many redstone contraptions, doesn't give a reliable 7gt signal anymore. Since 16w32 the signal length is random, which breaks countless things.