a piston unpowered from the block above by a long wire wont update
if you make a redstone wire on top of a line of blocks at least 12 blocks long and put a piston at one end and then power and unpower the other end, the piston extends when powered, but doesn't retract when unpowered.
to replicate:
build what is shown in 2015-04-07_22.46.10.png and turn the lever on and off
Environment
Linux 64 bit, Java 8 update 40
Created Issue:
a piston unpowered from the block above by a long wire wont update
if you make a redstone wire on top of a line of blocks at least 12 blocks long and put a piston at one end and then power and unpower the other end, the piston extends when powered, but doesn't retract when unpowered.
to replicate:
build what is shown in 2015-04-07_22.46.10.png and turn the lever on and offEnvironment
Linux 64 bit, Java 8 update 40



Dupe of MC-11193
That's a BUD switch. Place a block next to the piston to retract it. It's happened for a long time now!!