Redstone Machine Duplicator Not Working..

In addition to being posted in the wrong project this is working as intended.

I don't know if they completely patched it, as duplication exploits are considered to be security issues and are required to be made private on the issue tracker, but all evidence points to it being completely patched. This seems to be due to under-the-hood reworking of piston mechanics to fix some of their more severe issues. It IS fixed, as the old behavior was the bug, and a severe one at that.