Hi, I found this bug around 1.5 and was wondering if it was ever going to be noticed. However it was not and here I am. This bug is a client based issue and works on most servers. When the clock is activated (picture provided below) the sticky piston will fire rapidly causing and block in front of it to almost shake back and forth. If you then use another block and place it inside the piston (kinda tricky) this will seem to duplicate the block. In reality the block placed is still in your inventory even though it shows one missing. To the player who put it down they can stand on it and walk about. To everyone else there is only an air block yet the player is in the air. Servers with anti-cheat see this as flying. When the chuck is unloaded or the block get updated the glitch will go away. Id like to provide a video but cannot do so at this time. If you have any questions or need anything please feel free to contact me.