Not sure if this has to do with a bug with redstone timing or pistons; however, I am observing a bug with an elevator I built in a SMP that was once working until the latest Spigot update. How do I know? I replicated the issue on my own build of a local Minecraft server as found in the steps I took below: I downloaded the Minecraft 1.5.2 server and installed it. I installed this elevator world: http://www.mediafire.com/?q9v7pb2zlawvrgy I then started up my local server without any other plugins and checked that the elevator worked just fine. Next, I downloaded the latest version of Spigot, which is what my friend's server runs and then started the elevator again, and in this 2x2 elevator, some pistons either go up or down 2-3 spaces and stop, thus rendering the elevator broken. Don't believe me? Follow the aforementioned instructions and you will see for yourself. Please help!